Chatrooms have evolved in a really interesting way. I think the first generation to have them didn't fully understand how "public" they were. Maybe there are more people in the more recent generations that have a more visceral understanding of online "publicness" as they have grown up with (and perhaps have been burned by) those concepts from the very beginning. Maybe they have a better understanding of the permanence of online utterances and therefore have a more conservative approach to interacting on what feels like the permanent public ledger.
Maybe it's because the concept of pseudonyms has devolved since the early days. Corporate social media has an interest in doxing its users to advertise to and control them but pre-corporate social media was filled with anonymous usernames. Posting in a large group under your permanent forever name is much scarier than posting under an anonymous, temporary identity. One of the things I advocate people do is post online anonymously, instead of with their real name. It alleviates a lot of the fear of speaking your truth, which we need more of!
There is something there. The ability to try on identities in a safe environment before you discover which one you really identify with. It's much harder to do this with your real name. Your past comes with a lot of baggage and people who know you don't want you to change because it makes them feel uncomfortable.