There are a lot of threads I don't read. Usually, I read only if something looks interesting or appears to be a subject to which I think I might be able to learn something from and/or intelligently contribute to. I have to say that I haven't seen that much hostility toward the other place. Perhaps I missed something. Personally, I don't have any animosity at all. I left because of the new ownership and not for any other reasons. I know some people post both places, and that's fine. How much one wishes to participate anywhere is an individual choice.
While I understand the concern expressed about exposing newbies to the idea that most people can't make a living at writing, that is where we are--and where writers always were, if we're being honest. A few make a really good living, a somewhat greater number scrape by, a still greater number make a nice supplement to their income, and the rest of us make very little. That was true even during the early KDP gold rush. It's true even of trad published authors. That doesn't mean people shouldn't pursue writing. But, as I used to tell my students, "Follow you dream--but have a plan b."
As for the observation that the writing advice is mostly writing 101, I think that's inevitable for several reasons:
First, sometimes people who are enormously successful are too busy writing and marketing to spend much time on forums discussing writing and marketing.
Second, sometimes people who are enormously successful do participate a little and then stop because their advice isn't accepted. Sometimes, those instances are caused by other posters who are married to a particular theory and just don't want to hear anything different. I can understand how a contributor would be frustrated by that. Sometimes, that kind of issue arises due to misunderstanding. I've seen prominent writers take offense because someone suggests that their experience may not be applicable to people in other circumstances. (In fact, every single thing that works for Jim Bestseller may not work for Joe Prawn, and we see threads almost every day in which even people who are closer together in terms of performance report radically different results for the same strategy.) Either way, the authors involved end up staying away.
Third, sometimes people who are enormously successful would rather not reveal the details of their success. I want to emphasize that I'm not criticizing them for making this choice. Some methods might become less effective if everyone started using them. (Use of free promotions comes to mind.) There's also an understandable desire to monetize the secrets of one's success. (I might well do that myself if I had any secrets worth selling.) In some ways, this is probably the single most important factor that tends to make most free online market information fairly basic.
I'm grateful for people who do share strategies and results. I'm not surprised or worried by the fact that there aren't more of them.
I have found enough information on here to change my opinions on some subjects, so for me, the site definitely serves a useful purpose.