I think it boils down to a sort of "intellectual superiority complex" which is prevelent on the internet, especially in the venues you mention. You'll notice that in real conversations between actual musicians in real-life settings these debates rarely are had or are amicable and tasteful if they are. But the internet strips the personal away and people are able to just trumpet their own point of view with no regard to anyone else. So debates like tonality vs atonality are ripe for exploitation in this context. The "atonalists" often feel intellectually superior because they understand this grand technique that very few people understand and certainly the general public at large doesn't understand or like. They are the elite of the composers, the "best" of the classical music world and should be respected because they like atonality, dammit! Then you have the tonalists who hate anything that isn't tonal, and it becomes comical how each group fights the other. It reminds me a great deal of atheists and theists battling it out, as if atonality and tonality were fundamental philosophies on life and living! Of course, when I was younger and more naive I think I believed this to an extent. But through learning about atonality more and learning about how tonality isn't just I-IV-V-I, I began to appreciate the need for both, especially as a composer. Generally speaking I don't like atonality, I don't listen to it for pleasure (most of the time! :musicwhistle: ) but I can understand it and really dig into why it exists as a valid form of expression for an artist. And that's the goal of any discussion, eh? Understanding. I wish some other musicians would learn that, but of course that takes a lot of work and its simply easier sticking to your own POV and posting a YouTube comment.
Sith agrees too: :sith: