This is such a dumb take. For as much as I'd like to have a safer language in the kernel you need the current developers, the "big heads" at least because they have a lot of niche knowledge about their domains and how they implementation works (regardless of language) People shouldn't take shit like this from the ext4 developer, but it doesn't mean we should start vilifying all of them.
This guy's concerns are real and valid but were expressed with the maturity of a lunatic child, but they are not all like this.
Isn't Linux still Linux even though probably a lot of the original code is gone? Why would slowly rewriting it whole, or just parts, in Rust make it stop being Linux?