What a lot of people seem to think is that an inheritance is undeserved because the person receiving it didn't do anything to earn it. Obviously the parents earned this through their income and decided to not spend everything and give what remained of their wealth to their children. Even if the parents merely received their wealth from another inheritance they still had to decide to not spend more than they add to the inheritance, otherwise it would dry up over multiple generations.
Why do we even care about billionaires anyway? Why should I care e.g. that Bill Gates' networth is $78 billion? Why not care about the people at the bottom? Why not give them the things they truly need like financial security instead of letting them worry that if they earn too much their income drops. Either you're poor and heavily depend on welfare or you earn enough to not need welfare in the first place. There is no middle ground and the gap between the two is very large.