I presume that depends on who removes these posts. If the posts are removed by group owners or moderators who are not affiliated with the social media service itself, I think that should be totally fine according to that law. It's the social media service itself that's not allowed to do that.
I'm guessing it would be more practical to make a method by which dang could easily reinstate a users' messages/account after receiving the required legal documentation. I also assume it only applies to Polish citizens, filing the complaints with their courts.
