How do you feel about people who flip out on a friend who admits s/he had an affair?
I'm in the camp of those who think a friend shouldn't condone the act, but still be supportive. (Ya know, friendlike.) My flipping-out friend thinks cheating is wrong and verbally and emotionally flips out on cheating friends. Thoughts?
There's nothing in the friendship bylaws that says you can't end a friendship with someone who serially and unapologetically cheats - or lies, for that matter, or otherwise treats other people like dirt. The strength of a community reflects the strength of the individual friendships within it, and so it's both natural and healthy to keep your distance from people who knowingly undermine others for their own gain.
But, to borrow your language about your flipping friend: Who actually thinks cheating is right? For that matter, how many people who try to rationalize it even come close to succeeding? No doubt there are some, and good for the friend who has the courage to challenge any self-serving justifications.
However, when a friend admits an affair and is in any kind of perceptible pain, then flipping out on that friend isn't an act of moral righteousness, it's an act of presumption. As if the cheater needed this friend to point out that cheating was wrong.
The most "friendlike" option, in my opinion, is to take for granted that your friend knows right from wrong, and knows cheating is a mistake - or else, again, this person is not someone you'd want as a friend - and to be available to help this friend start sorting through the damage.