why not confront these deniers and prove the holocaust happened, rather than deleting their posts and banning them?

For cases of Holocaust denial or "Just asking questions, dude" (a rose by any other name, &c), the mod team has a prepared response. We post it to removed questions and provide it via modmail to users who receive a temporary or permanent ban.

The macro is the character limit for a reddit post, so I will provide it in a follow-up.

I can't believe that in 2016, a canned response to Holocaust denial is still necessary.

We have discussed this various times in various threads and /u/elm11 has already given a variety of reasons, why we remove posts by Holocaust deniers. You can also find more about our reasoning here and here.

I'm especially fond of this quote by Deborah Lipstadt that /u/Georgy_K_Zhukov used:

I once was an ardent advocate of ignoring them. In fact, when I first began this book I was beset by the fear that I would inadvertently enhance the ir credibility by responding to their fantasies. But having immersed myself in their activities for too long a time, I am now convinced that ignoring them is no longer an option. The time to hope that of their own accord they will blow away like the dust is gone. Too many of my students have come to me and asked, "How do we know there really were gas chambers?" "Was the Diary of Anne Frank a hoax?" "Are there actual documents attesting to a Nazi plan to annihilate the Jews?" Some of these students are aware that their questions have been informed by deniers. Others are not; they just know that they have heard these charges and are troubled by them.

Not ignoring the deniers does not mean engaging them in discussion or debate. In fact, it means not doing that. We cannot debate them for two reasons, one strategic and the other tactical. As we have repeatedly seen, the deniers long to be considered the "other" side. Engaging them in discussion makes them exactly that. Second, they are contemptuous of the very tools that shape any honest debate: truth and reason. Debating them would be like trying to nail a glob of jelly to the wall.

Though we cannot directly engage them, there is something we can do. Those who care not just about Jewish history or the history of the Holocaust but about truth in all its forms, must function as canaries in the mine once did, to guard against the spread of noxious fumes. We must vigilantly stand watch against an increasingly nimble enemy. But unlike the canary, we must not sit silently by waiting to expire so that others will be warned of the danger. When we witness assaults on truth, our response must be strong, though neither polemical nor emotional. We must educate the broader public and academe about this threat and its historical and ideological roots. We must expose these people for what they are.

What it in the end comes down to is that we do not want to engage with outright Holocaust denial in this space we curate for the same reasons, we have a rule against political soapboxing: It isn't conductive to discussion and does not serve an educational purpose for giving them a forum to spread outright lies with a political agenda is not what we do here.

We are of course making sure that questions coming from a place of confusion or questions about Holo9caust deniers and their arguments do get answers. I have done so myself in the past for example here where I addressed various claims made by the well-known Holocaust Denial organization, the Institute for Historical Review, here where I address claims frequently brought up by deniers about the death count of the Holocaust, or here where I go into the 6 million in Russia thing some deniers also use.

From reading and addressing all these things, I have learnt another thing about deniers and their way to argue: The discussion will naver take place from the same basic assumptions because deniers care not about truth. They pick small details, take them out of context and then and when you explain it to them, they will flat out deny that the evidence presented has any value or find something else to latch on. As Lipstadt says: "Debating them would be like trying to nail a glob of jelly to the wall."

Every question here that gets answers about the Holocaust is enganging with deniers on some level because we get the information necessary out there. But to give them a forum here to be debated when their world-view is a construct of lies with a nefarious political agenda is not something we do or want here.

That there is overwhelming evidence, but people still deny the holocaust, is proof that those people have no foundation in reason. No argument or confrontation, no matter how thorough, or how elegantly worded, is going to change those people's minds. Trying to interact with them is a waste of everybody's time. And if deniers ever feel like actually educating themselves, well, there are plenty of other resources for them to turn to.

The short answer? We have better things to do with our time, like bang our heads against the wall. The long answer? Well, my feelings are very well expressed by Deborah Lipstadt:

I once was an ardent advocate of ignoring them. In fact, when I first began this book I was beset by the fear that I would inadvertently enhance the ir credibility by responding to their fantasies. But having immersed myself in their activities for too long a time, I am now convinced that ignoring them is no longer an option. The time to hope that of their own accord they will blow away like the dust is gone. Too many of my students have come to me and asked, "How do we know there really were gas chambers?" "Was the Diary of Anne Frank a hoax?" "Are there actual documents attesting to a Nazi plan to annihilate the Jews?" Some of these students are aware that their questions have been informed by deniers. Others are not; they just know that they have heard these charges and are troubled by them.

Not ignoring the deniers does not mean engaging them in discussion or debate. In fact, it means not doing that. We cannot debate them for two reasons, one strategic and the other tactical. As we have repeatedly seen, the deniers long to be considered the "other" side. Engaging them in discussion makes them exactly that. Second, they are contemptuous of the very tools that shape any honest debate: truth and reason. Debating them would be like trying to nail a glob of jelly to the wall.

Though we cannot directly engage them, there is something we can do. Those who care not just about Jewish history or the history of the Holocaust but about truth in all its forms, must function as canaries in the mine once did, to guard against the spread of noxious fumes. We must vigilantly stand watch against an increasingly nimble enemy. But unlike the canary, we must not sit silently by waiting to expire so that others will be warned of the danger. When we witness assaults on truth, our response must be strong, though neither polemical nor emotional. We must educate the broader public and academe about this threat and its historical and ideological roots. We must expose these people for what they are.

I find a lot of wisdom in what she wrote, and my approach to dealing with Denialism is my best attempt to comport with that Ms. Lipstadt wrote about there. And as she writes, it isn't about "engaging them in discussion or debate", as you might as well just be bashing your head against the wall. It is about doing your best to educate, and even though we take a very firm stance when it comes to Holocaust denial, we do our best to ensure it isn't at the expense of education. Asking questions about the Holocaust isn't banned by any means, and even impolitic questions are not going to be automatically shut down. We do understand that sometimes, someone who is honestly confused and looking for guidance might sound suspiciously similar to someone who is posting very much in bad-faith and their intent is to seed doubts or an excuse to link to their favorite video about the Jewminati. We evaluate those on a case-by-case basis, and do our best to suss out the intent of the author since, obviously, in the case of the first the worst reaction they could get is to be shutdown and banned from the sub!

That's not how they work. Any evidence against a conspiracy is a fabrication in their minds, & therefore proof of an ever-deeper conspiracy. There's no point in arguing with someone like that.

Here is yet another post that discusses denialism. Remember that a key to this is that when a person is a denialist, engagement with them is a win. It gives esteem to that which has none. They don't broker in truth. Any amount of "information" that they are able to get an audience for is a victory for them.

Compare though, the post linked above where the people seemed to have genuine questions about some aspects of denialism. The person wasn't banned and people came to help give answers.