You're seeing the posts in his blogs. His timeline was full of bashing devs of other open source projects. Never a constructive criticism, just plain bashing (with occasional self-congratulatory comment for his own decision).

PS: I think part of his Rust criticism was towards the attempt to make Sway use wlroots-rs and it not fitting his idea. So, instead of saying "Sorry, it didn't work", he jumped into full bashing Rust for not doing what he was trying to do.