The author knows C++ (https://github.com/simdjson/simdjson https://github.com/simdjson/simdjson) and writes a lot about his performance experiments. I don't see

The author knows C++ (https://github.com/simdjson/simdjson https://github.com/simdjson/simdjson) and writes a lot about his performance experiments. I don't see why he - or anybody else - shouldn't raise such questions and arguments without having people (like you) getting angry about it. Is it offensive? Anyway, he has a point, `cout` is used extensively as a logging mechanism. If you don't see that "single millisecond" making any difference, you certainly haven't work on a relevant system.