Twitch chat is for emoting, especially in ways that please the streamer. Trying to actually chat with someone on an active Twitch channel is futile.

But YouTube has also completely destroyed their entire concept of having a "YouTube community" over the years. There might be something of various creator communities in various niches, but the heavy censorship, mess of a comments section that does everything in its power to halt any form of conversation, leaving only spam and idiots in most comment sections, etc. left it with nothing of a community, or any real creator/consumer dynamic.

YouTube no longer has private nor direct messages, so if people want to communicate they have to do it on another platform. It's also just a bit of a mess with the transition from the original idea of "everyone has an anonymous handle" to "every must have their Google+ profile linked and use their real name" to "Google+ is dead and now some people have silly handles and some people are real people." The whole thing adds up to make for a place with no coherent community.