I think there are a few things going on here.
Yes, every since the old Gnu Social days there have always been techie-elitists on the fediverse who say things like "it's good that it's hard to use because it keeps the 'normies' out" ... and alas, that tradition continues today on Mastodon and other platforms (and is often expressed in language that echoes anti-immigrant tropes or is somewhat racist). It's unfortunate but I don't know what we can do about it other than attempt to minimize their influence.
There's always been a tension between people who are in the fediverse because they want to get away from big tech companies ... and people who are in the fediverse because they think decentralization is cool, and so see it as a good thing that big tech companies are adopting the technology because hopefully over time it will provide a path for people to move off of the big corporate social networks. When Eugen called Threads' adoption of ActivityPub "a victory for our cause", it really drove home to a lot of people that his cause isn't theirs. This is part of why I talk about fediverses in the plural: there's a corporate fediverse as well as the "free fediverse" that's anti-surveillance capitalism (and others as well, like the 'freeze peach' fediverse). Of course, the various fediverses can potentially co-exist, but motivations and values are very different ... and the bigger corporations looking at the fediverse certainly aren't going out of their way to help or even acknowledge long-time fedi developers who aren't directly useful to them, so there's almost certainly some resentment on that front.
ever since 2017 (if not earlier), the fediverse has been very driven by trans, queer, and non-binary people. So if the fediverse is 100x larger with big players, and in the process it becomes 99% cis-dominant, then yes they have really taken soething away from trans people. What percentage of the speakers at Fediverse House were trans? Which speakers talked about the key role trans and non-binary people have played in Mastodon and ActivityPub's development? And since the biggest player is Meta, who's actively hostile to LGBTQ+ people, the dynamics are even worse -- especially since so many high-profile cis fediverse influencers only talk about the positive aspects of Threads without even acknowledging the concerns of trans and non-binary people. How many of the speakers at Fediverse House mentioned the anti-Meta FediPact and Vanta Black's perspective (shared by many of the signers) that "being okay with meta joining the fediverse is being okay with cosigning every goddamn trans person who chooses to remain on here to a future of constant harassment"?
Of course the second and third bullets aren't directly relevant to NodeBB. You're definitely grassroots and DIY. And getting new perspectives and energy from people like you -- or the 2022 wave -- is crucial to getting ActivityPub out of the rut it's been in for the last N years, and making the software more broadly usable. But they're certainly part of the overall dynamics.