Part of the hostility was the other maintainer misunderstanding the presenter, going on a diatribe about how the kernel Rust maintainers are going to force the C code to become unrefactorable and stagnate, and rudely interrupting the presenter with another tangent whenever he (the presenter) tried to clarify anything.
An unpleasant mix of DM railroading and gish galloping, essentially.
I wouldn’t quite call it a strawman, but the guy was clearly not engaging in good faith. He made up hypothetical scenarios that nobody asked about, and then denigrated Rust by attacking the scenarios he came up with.
Edit: I was thinking of the wrong fallacy. It is a strawman, yes.