It depends I suppose. It's no more a time waster than reading a book or watching a movie or playing a game (because none of these things are considered productive by people who get to decide such things). In the big picture (as in, the entire span of the history of the universe), everying one does is a complete waste of time.
That said, I don't think it's a waste of time per se, but if someone comes to a simple or stupid conclusion after a long period of deep though, maybe the time was indeed poorly spent.
That said, I don't think it's a waste of time per se, but if someone comes to a simple or stupid conclusion after a long period of deep though, maybe the time was indeed poorly spent.