Earlier quoted context omitted.
China bans plenty of US apps and services. Facebook, for instance. They are exactly comparable.
If you comply with China's laws you can operate there. These US companies just don't want to deal with that.
The problem is that China's legislation and jurisdiction are in a complete control under a single political entity, CCP and its laws are deliberately designed to be ambiguous to allow arbitrary interpretation in favor of CCP. Also, don't forget that CCP's constitution is on top of PRC's constitution.
Obviously, this situation is not acceptable in the the principle of free trading as CCP is blatantly exploiting this political system to discriminate foreign companies and effectively violate the principle of national treatment. In order to join the global free trade system, a long time ago China promised to change its political and economical practice at least minimally compatible to other states. I think the previous presidents till Hu Jintao might keep it in their minds but unfortunately Xi Jinping doesn't seem so.