How are monarchy's and dictatorships the same?

Although a monarchy is supposedly better than a dictatorship, they are similar, because both types seem to oppress the people. A King or queen could easily be looked at as tyrant or dictator. They can do and say as they please with no repercussions. Any one who believes something that opposes their views; can easily be "dealt with." Look at Hitler, he killed people he thought were unclean or not pure, and many king have ainated people for personal reasons. (King David killed a man, took his wife, and had a baby out of wedlock.) Basically, both really don't care about the people, but more or less their wants and desires.