It's not whataboutism to point out that every great power, for thousands of years, has done that same thing.
Why's it worse in this case?
It's not worse. It's just bad and it'd be better if they'd stop. The US too.
There's a lot of bad stuff that isn't going away. Global powers projecting that power in various ways is one of them. It would absolutely be better if the US/China didn't do the bad things they have done. Good luck stopping that from happening in the future, it's been happening since civilization was created.