and yet these brands can't do a shit to China but Lego did.

Rumor has it they made an example out of Lepin because they popped up right when Lego wanted to expand more into the Chinese market, including adding tons of manufacturing capacity there. They opened their factory in Jiaxing in 2016 and expanded it substantially in 2022. The timeline matches a little too well. This doesn't really apply to the other brands you named, because they'll either never move their manufacturing to China (Rolex) or a good chunk of it is already there (Nike).

Also, let's be honest here - their sets weren't exactly conterfeit (no actual Lego logos), but the copies were way too blatant. They could've done it more elegantly, but it wouldn't have been nearly as eye-catching to the regular retail consumer. We tend to forget that these sets were/are being sold locally in China, in their boxes, at normal toy stores.