I'm on Voyager (via the app store) and it is wonderful (and free)!
I agree that some communities are quite empty, but I found that the techn savy communities are quite large and well maintained (selfhosted, linux and such).
Although the read is arguably shorter, i have more time in my day as a result of that. Not missing reddit at all ATM.
Aside from that I think C is more performant than C++ (indeed when you use the bells and whistles that C++ offers), you are comparing the libraries with each other.
The fact that the implementation of one random std::Sort is faster than the implementation of qsort() is comparing libraries, not the languages. You are comparing the algorithm of the Rust Sort with quicksort (which is obviously the qsort you are referring to.
I am certain there are sort implementations in C which outperform Rust.
Having said that, I immensely enjoy Rust because it forces me to think about the error handling and it does not give me the quirks of C/C++ (index out of bounds, memory corruption).
I dig the analogy and had to chuckle.