Yes, it is. But you can't chat if the messages scroll by to quickly. Just watch an asmongold stream live if you want to see an extreme of what they were talking about.
100-200k people writing in the same chat is just too much for anyone to read it
Chat becomes highly memetic in large channels but that's part of the fun and highly engrossing. It's like being at a concert and becoming fully immersed with the rest of the hive mind. Many religions base their practices around this feeling of collective ecstasy, only on Twitch it's by using a sea of pogs and pepegas.