Yes, this is wrong in that sense, but by learning C you learn how C works, and therefore how your computing systems, which are going to be C at some level because we live in Unix's world, work.
I think this can trip newbies up. Especially from bootcamps, who don't understand why their code is working, and I feel like replying with "well think about how the object is stored in memory" because none of the stuff that's built on that will make sense without it. I'd like to understand more myself. It would be useful to have some idea of what the compiler is doing with things like lexical scopes. I think that's the only way to really understand them as the abstractions are too leaky.
I dont mean you can then write these languages, but you can look under the hood and read the source code (also if you want to write extensions it is useful).
You mean, of CUDA kernel programming. The basics of CUDA as an ecosystem are not that much about a particular language and there are bindings for many languages.