I find these "the same people who argue for/against X are the same people who argue for/against Y" comments odd. Do you have a specific example of this outside

I find these "the same people who argue for/against X are the same people who argue for/against Y" comments odd. Do you have a specific example of this outside of politicians*, or are you lumping everyone in camps X and Y together without proof of significant overlap? *Politicians don't start from "I believe X/Y, let's do something about it." They start from "How do I get my voters agitated and eager to vote for me, and what position should I take on controversial issues X/Y during an election year to achieve this goal?" Politics/electioneering is showmanship first. Silly things like real personal political beliefs only get in the way of politicians' end goal of power.