The problem is that we have no idea what you're talking about when you say C/C++. For you it seems to be C++, for someone else it might be both or it might be "one or the other but I don't know which." For yet someone else it might be really just C.
If you were to think that Rust is a good replacement for C++, why not just say that Rust is a good replacement for C++? That makes it clear what you mean, and thus the obvious follow-up: a lot of people would like a replacement for C, which is arguably not what Rust is.
And this is very on-topic for a discussion where someone asked "why Zig over Rust?" Zig is arguably closer in spirit to C than Rust is.
When you say Rust is a good replacement for C/C++, a lot of people read it as if you were treating C and C++ as one language and that Rust is a good replacement for both. It should not be hard to see why this is very controversial, given that they are very different languages and people tend to like one and dislike the other. It's going to be very hard to please both camps.