Political jobs would be torture for most people. You have no freedom. You are underpaid and over-bugged. You lose a lot of your privacy. You have to stop writing emails or saying what you think. You don't get to read many good books or go for many quiet walks. It's hard to be a non-conformist. And so on.
Yet it's really hard to get top political jobs. So who gets them? People who truly, deeply love the power.
Plus "doing what the voters want" very often feels like, or can be described as, "doing the right thing."
So what happens when those people perceive their power as threatened? You see it.
One implication is that paying politicians more, and giving them more privacy, would lead to less craven behavior. (Although I personally don't like the current bill, the D. refusal to pass it is sheer cowardice.) There would then be less selection for the "power addiction" and perhaps more principled behavior.