This totally might be true, but the fact that he got as far as measuring the same latency on X and Wayland… and then just gave up and is like “well never mind what the measurements say, it’s definitely Wayland”… Hmm.
You gotta do the measurements. It’s probably not even that hard, all you need is a USB mouse emulator (any microcontroller with USB peripheral support can do this and there are tons of examples) and a photodiode.
You don’t even need to worry about display latency if you are just comparing X with Wayland.
Pff it’s not like Linux has perfect WiFi either. I set my WiFi to auto connect to a VPN, and then delete the VPN later. That caused WiFi to always fail with no error messages except some incomprehensible deauth message in dmesg! Good luck figuring that out.