I agree it's rude, offensive, and hostile, but there are degrees of things and context matters. "You are cancer" would be much worse. I feel we should try and interpret things in good faith and maintain some perspective. For a single word like this: you can just read over it (which is also what the other Rust people did).
Certainly outright removing Hellwig from the Linux project, as Marcan suggested, is bizarrely draconian.
As I argued a few days ago: part of "being nice" is accepting that people aren't perfect and dealing with that – https://news.ycombinator.com/item?id=42940591
He said: “ And I also do not want another maintainer. If you want to make Linux impossible to maintain due to a cross-language codebase do that in your driver so that you have to do it instead of spreading this cancer to core subsystems. (where this cancer explicitly is a cross-language codebase and not rust itself, just to escape the flameware brigade).”
I think the conversation is more about people equating R4L as validation for rust or even themselves.