A lot of it

stems from the idea that a politican can legislate based on certain morals, values, etc. that they profess to having, that they campaign on, that they speak about a lot. Barney Frank? Sure, he was caught with a call...boy. But he's openly gay. He wants equal rights for gays and lesbians. That's his whole deal, along with marijuana and gambling .

Man, Barney Frank. Representative that's fun to hang out with.
Anyways.

It's not the affair, it's the hypocrisy. And sure, we all know at this point that politicians lie a bunch. But in this day and age, we have people legislating about marriage, about families, about all sorts of things. It might be a...I think it's ad hominem tu quoque to say that disqualifies him from his job, but in a sense it disqualifies him from presenting himself as an authority on the subject, which is what congresspeople have to be in some sense. Being a husband, being a wife--when you're making laws around marriage and family, these things suddenly become part of your job description. They're relevant to what you do.