I am pretty sure it was about how it was difficult for them to do oop with rust, but I reckon it was long ago and my programming knowledge is minimal.
Found it:
https://rl.rootdo.com/r/rust/comments/yuxb8a/serenityos_author_rust_is_a_neat_language_but
I vaguely remember the talk about needing oop for the web being on discord and not twitter, so the twitter post is likely a reaction that.
It could be. But then again, he did have the help of a Rust designer/core dev. I believe they even wrote the first iteration of the “Jakt” compiler in Rust before rewriting it in Jakt itself, so Andreas isn’t against using Rust.