Human beings can live together in a free society only by respecting one another’s rights. Of course, there are many other sorts of societies that can exist, such as dictatorships. But, for a “free” society to exist, mutual respect for rights is a necessity.
Any person who does not respect the rights of others (by, say, stealing) shows through their actions that they do not accept the concept of rights. After all, you can’t both accept a right AND reject that same right to someone else, since this would entail a contradiction. Therefore, it is morally acceptable to remove rights from those who would deny rights to others.