Agreed. Take a look at https://www.techempower.com/benchmarks/#section=data-r19&hw=...

C# currently 1st place in this webserver benchmark. Ahead of C/C++/Go/Java/D.

No offense to JavaScript, I like it and it has its uses. But surely your OP is joking when saying JavaScript is faster than C#. Even after all the performance improvements that V8 received.