"Yes all politicians are self serving crooks"

The problem with that "argument" is that most politicians could do rather better for themselves out of politics. And most local politicians get little reward for their efforts.

In my experience most politicians are trying to work for their communities. I may agree or disagree with what they are doing but I do not doubt that they are doing their best according to their own political creed.

The advantage of the above comment is that it does not require the speaker to think rationally about the realities of policy decisions before coming out with it. It is far easier (and quicker) simply to write off the political process in a quick spasm of cynicism.

Which is a shame because we need people to think rather than just turn away.