People vote in rigged elections, whose electoral mechanics are decided by the people who have the job, not the people who vote. They are granted immense and immeasurable power, that no company monopoly has ever matched. They are purposefully corrupt, purposefully manipulative, purposefully abusive, in smart ways, sometimes. The people below them are mostly helpless. You go ahead and vote for anyone in politics, they're all literally in there for the same reason outside of a handful. They want wealth. They want power. They want to abuse others. There's no magic to it. They are the best candidates for it. The most likely to win. They are willing to lie, cheat, scam and so on. And you've granted them immunity from lying, from abusing, from starting criminal things, from doing criminal things, and so on. Not the immunity one has with power, but the immunity has with legalised power. You've literally given them a system where raising your hand gets you shot. Where the only allowed shooting is theirs. If you can't see how this is vastly different from a system where shooting by anyone at all is bad and wrong, and actionably so, WHETHER OR NOT you think it is likely that you can do much about it, I don't know what to say. They are fundamentally different.
The other thing is, we've seen good kings, we've seen bad ones. We've seen middling ones. We've seen tyrants, we've seen leaders who try to free and help. We've seen mixes. We've seen people blackmailed into things, and so on. It is reductionist to imply otherwise. To imply that no one has ever been good, no one has ever been uncorrupt, is silly. The problem is, when you make a system that maximally incentivises and protects the worst, it makes it highly likely all the good people are outcompeted, destroyed, and so on.