KYC is also mandatory on bybit. I think the main different was in the event created by the exchange sites. I was bybit users and i often particpated in the token splash along with almost one hundred thousands of people in bybit. The event is pretty much the same like airdrop by doing fast trade and i can get decent amounts of money.
I was not even found this kind of event on bitmex, which is lack of regular event. This is why the majority of people were moving their money from bitmex to the exchange site like bybit or binance which is regularly launched various event the helped us as users to generate more money through in safest way.
Bitget was also very often create big events like bybit and binance, its bitgetwallet is always working with the various new projects in order to increase their engagement to the users. Bitmex was rarely doing this.

I believe it's caused by lack of events on bitmex. it's not related to the KYC. People are seeing identity requirements are just a common thing these days. Only some people who against it. kind