This may sound weird to you but this is very important to me. I once also believed everything someone said on the internet just because he cited some books. But i have a friend who once studied history and he told me that if someone doesnt cite pages, what he writes should be taken with a heavy grain of salt. Why? Theres 2 reasons:
If someone doesnt cite pages it could be that what he writes down is from his memory and he thinks that he read it in that book. But if he actually cites pages you can be sure that before making his claim opened the book and so you can be sure that it was surely from that book and not something he thinks he read.
Not citing pages makes it very hard for people to verify your claims. This is probably the more important reason. If someone doesnt cite pages, it will be very hard for you to verify what he claims is true or not if he cites a 700 page long book. So he basically says "Fuck you" to everyone trying to verify the accuracy of his claims. And what does this say to the credibility of his claims?
Many people may not care at all, but I do because this is the internet and people can write alot of bullshit, especially on Reddit. Just because this is a subreddit dedicated to historical questions with high standards doesnt mean that what someone writes isnt complete bullshit, even if he is a known member of the community.
And sadly most submissions to this subreddit dont include cited pages, so it is very hard for me to find answers to my questions which i can trust.
Yes, in academic papers this is absolutely true. But you have to understand that it takes a great deal of work to properly cite every argument that you make, and it is simply too much to ask of us to properly cite every detail of a response as if we were preparing an academic work.
If you really want to know about something specific, however, I am always happy to put together a proper citation for a point that I've made, which can take days if I do not have immediate access to a book or article that I've cited (a lot of the primary material that I personally cite, however, is found officially online on the State Department's website, and so I have an advantage in that sense). It's not fair at all, however, to assume that I do not properly remember the thesis of a book that I've read just because I do not have it on me at all times.
Keep in mind that this subreddit is run by actual historians, i.e., folks who have gone through far more rigorous training in the field than someone who studied history only as an undergrad. Also keep in mind than none of the answers here are expected to meet the requirements of a journal or academic press. My point here is that historians have created the rules for a proper submission here with strong knowledge of the best way that we can provide high-level answers on an internet forum, and the rules here are indeed far stricter than any other subreddit that I frequent.
Nevertheless, I agree with you to a certain extent, in that I sometimes, too, get the impression that a random responder has cited a book (sometimes an article) without that point in-itself really existing in the original work. Always doubt what you read, even if it is properly cited! In these cases, I typically ask followup questions that give me a better feel for how well the responder knows the source material that they cite, and yes, there have been a couple of times that I've even asked for a more specific citation like you suggest.
One issue is that sometimes I, like everyone else, misplace books! My copy of "White Eagle, Red Star" by Norman Davies has been missing for about a month and I might cry if any questions (of the 0 which have been asked thus far) about the Polish-Soviet War pop up. I see where you're coming from but also remember that relatively generic citations are far better than none at all.