That depends on tge terms of service and the jurisdiction you are based in. And whether or not you want to go to court over it or not. IANAL, but I am fairly certain terms of service do not trump national copyright laws. At max, you might forgoe some usage rights, copyright will stay with you (at least were I live, as you cannot sell copyright, only usage rights if I understood, and remember, the finer points of our laws aroubd that stuff correctly).

That bog tech gets away with, is not necessarily because it is legal, but rather that people don't care, law makers only start to care and even if people would care, it is nigh impossible to successfully litigate.

None of the above is written in stone, nor should it stop us from doing something about it.