I have a suspicion as to why this perception exists in the C++ crowd.
I don't think it's because of evangelists. C++ was that evangelized language in the early 90's, but after a period in the sun it then survived the evangelism of Java, Python, Go, and others, despite losing ground to them in general purpose tasks.
And that's because all of those other languages, while being much safer than C++, came at the cost of performance or the overhead of a runtime. There was really no other language that had the expressiveness of C++ while allowing the developer to get down to the bare metal if they needed speed.
The existence and growing popularity of Rust changes that calculus, and I imagine that makes certain developers who might have a lot of investment in the C++ ecosystem defensive, causing them to overreact to any perceived slight in a way that other languages simply don't provoke.
That is, nobody perceives, say, "the silver searcher" as being some sort of nefarious plot to re-write grep, but they did with ripgrep, even though that's not what it is trying to do.
There are a few projects that are deliberately doing a re-write for reasons they consider important, but they're not "just because it's in Rust," they're things like "openssl has had memory safety issues, we should use tools that eliminate those" or "sudo is very important and has grown a lot of features and has had memory safety issues, we should consider cutting some scope and using tools that help eliminate the memory safety issues." But those number of projects are very small. Heck, even things like uutils were originally "I just want to learn Rust" projects and not some sort of "we must re-write the world in Rust."