Part of being a good developer is the “working well with other human beings” part. Linus himself took a hiatus to improve himself in this area.
Another part of being a good developer is to work within and adapting to the frameworks of an existing project, especially if you are joining at a later point. In this context, it would be the R4L folks joining the project known as “the Linux kernel.”
Hector failed on both counts. He has programming skills, but that’s not all that’s required.
If you had read Christoph’s reasoning, it wasn’t “just because it’s written in Rust.” He actually gave some decent technical reasoning for it that went beyond his original personal outburst (which I hold him to the same standard as Hector for, but he did shore up later and fixed his communication).