Part 1

If I may start with a recommendation: Since this is your second question in two days concerning the Holocaust, we do have an excellent book list with a lot of recommendations, some very easy to read and come by either in your local library or on the cheap in your local bookstore or on Amazon. And some of it short and modeled as an intro to boot. Just because those are much better sources of information than any Holocaust denier video on youtube. In fact, I'd tell anyone not to watch Holocaust denier videos on youtube and this is another perfect example for why.

Holocaust deniers work by picking very small details, half truths and outright lies, placing them outside of the crucial context for their understanding and from them spinning an unsupported interpretative narrative about the whole of the Holocaust. Jan van Pelt succinctly addresses this issue in regards to the swimming pool in Auschwitz I Stammlager in his report for the Irving v. Lipstadt Trial:

A favourite example of the negationists is the so-called swimming pool in Auschwitz I. They argue that the presence of a swimming pool, with three diving boards, shows that the camp was really a rather benign place, and therefore could not have been a center of extermination. They ignore that the swimming pool was built as a water reservoir for the purpose of firefighting (there were no hydrants in the camp), that the diving boards were added later, and that the pool was only accessible to SS men and certain privileged Aryan prisoners employed as inmate-funcionaries in the camp. The presence of the swimming pool does not say anything about the conditions for Jewish inmates in Auschwitz, and does not challenge the existence of an extermination program with its proper facilities in Auschwitz II.

In this way of going about it, Holocaust deniers bank on a certain popular idea of Auschwitz and the Holocaust at large – though deniers focus mainly on Auschwitz – and the fundamental basic incomprehensibility of the reality of such a place as Auschwitz and the reality of the Holocaust. Because we as a public – thankfully – lack en large a frame of reference to truly grasp the historical reality of places such as Auschwitz, Holocaust deniers often seize on such details and draw from them conclusions that are simply not supported by the available historical evidence.

Auschwitz I Stammlager had indeed a swimming pool. But the answer as to how the presence of a swimming pool, adapted from a water reservoir, does exactly negate that Auschwitz was a place for mass murder is one that Holocaust deniers do not deliver. They work through insinuation and argue that if there was a swimming pool, how could it be a center for extermination without explaining exactly how the presence of a swimming pool primarily for SS-personnel does invalidate Auschwitz being a center of extermination. Why is the fact that the people carrying out mass murder in that place enjoyed a swim somehow contradictory to the idea that murder on a massive scale was carried out there? Do murderers not like to swim, read, or listen to music?

In the Auschwitz camp complex there existed a swimming pool, a soccer field, an orchestra, and a daycare for children of SS-personnel. At the same time it was a place where at least 1.2 million people were murdered. How this goes together will emerge from crucial historical context, which every historian will tell you is the key to historical research: Properly contextualizing phenomena in order to explain them. Unlike Holocaust deniers who purposefully omit context or contextualize wrong to serve their nefarious and bigoted agenda.

First of all, Auschwitz was not one camp but a complex of different camps: Auschwitz I Stammlager was a Concentration Camp in the sense of Dachau or Buchenwald, meaning it was a place with the specific purpose of imprisoning real and alleged political and "racial" opponents, exploiting their labor, and killing some of them. Auschwitz II Birkenau was both a place to exploit labor but also for large scale murder: Similar to the Reinhard Camps and Chelmno, a major focus of its existence was to murder thousands and hundreds of thousands of people upon their arrival in the camp with only select few to survive arrival and be subsequently exploited for their labor with the purpose of working them into a state where they'd either die by themselves or be killed by the camp administration for having outlived their usefulness. Auschwitz III Monotwitz was a camp build with the expressed purpose of constructing a Buna (synthetic rubber) factory for the IG Farben, one of the major industrial partners for the SS, with political and "racial" opponents having to do forced labor under inhumane conditions for the IG Farben.

Auschwitz I Stammlager in line with it functioning like a concentration camp rather than a death camp (this doesn't mean that a lot of people died there or were killed there btw., rather it means that its expressed purpose was not the systematic murder of Jews and Roma) had hardly any Jewish inmates and developed an internal social hierarchy along the lines of those camps in Germany. In practice, this meant that the Nazis created an internal hierarchy among the prisoners designed to make their administration of the camp easier and dangle rewards like being able to swim in the pool as a carrot for prisoners in order to make them complicit in their own oppression. As in other camps, being able to swim in the pool, visit the bordello, and play soccer was used as a way to make non-Jewish, mostly German prisoners act in accordance with the guidelines and wishes the Nazis laid out for them, such as in running work details, administering things like the camp kitchen and so forth.

This perfidious method of integrating the prisoners into their own oppression was a marked element of the Concentration Camp and despite the work with these rewards, the underlying insidious power dynamic with life and death calls on the hands of the SS never went away. In the Mauthausen Concentration Camp for example, the camp administration once organized a soccer tournament where SS-guard teams and prisoner teams played against each other. The prisoner teams who won were killed in the aftermath.

Similarly, the orchetra in the camps, including Auschwitz: Playing in the orchestra was a privileged position for prisoners that went along with better clothing and food. But it was by no means safe. In Auschwitz, Höss once had half the orchestra killed because he didn't like their interpretation of his favorite marches.

The other aspect that needs to be considered here and that is often forgotten when talking about these things is that for the SS-personnel, Concentration Camps and even death camps were a place of work. Most of them had houses there – here are the houses formerly used by guards in Mauthausen where people still live today –, because they were not local they brought their families with them, including their children and wives, and with that came a broad range of offerings for these guards and their families to spend their free time, including swimming pools, soccer places, day care and a library. All these things served the essential function of making those people who on a daily basis organized the oppression and mass murder of people as cozy as possible.

Here's a photo of male and female guards at Auschwitz having a little celebration in their free time, here's a photo of some guards drinking together on their day off, here are some guards resting near a retreat especially build for Auschwitz personnel to relax.

It is a fundamental fact of the guards' and administrators' lives at Auschwitz that after a day of gassing thousands of people, of shooting and beating prisoners, of having them work and starve to death, they would go home into their nearby houses to their wives and children to spend evenings and weekends that were totally "normal" in the sense of doing stuff people in every other job, every other profession do to: Have meals, loan a book from the library, go for a swim, a walk, a drink. And the larger organization of the SS had to make sure they have these amenities like every other employer who wants to keep his employees happy: So they build a pool, a library, and a day care center for guards and their families, all using prisoner labor from the camp.

We have in fact, diaries and letters from people working in Auschwitz remarking how wonderful life is there even despite the constant smell of burning human flesh from Birkenau but as many put it, that is just a minor inconvenience given how wonderful the job and life is there, including having prisoners as their house personnel doing their cleaning and cooking (in most cases these were female Jehovah's Witnesses). That was even part of the package they were promised for working there: To live in conditions most of the guards and their families would have been unable to afford otherwise, including big houses, house personnel and their private recreational facilities.