"Aggressive disagreement" is one thing.
Incoherent passion is another.

I don't especially like to talk to someone who's shouting, especially when it's mostly invective that's light on semantic content, but I respect other people's right to shout and shout back. The thing that bothers me is that so often the shouting seems to be at the expense of facts. Numbers that sound for all the world like valid statistics, rumors repeated as truth, quotes from celebrity figures as though they're speaking ex cathedra, and on and on.

I always know that a political discussion is going to go nowhere at warp speed if I get yelled at for asking for the source for a fact. Honestly, if you don't know the source, or you can't establish the source's bona fides, I don't see anything wrong with adding "I heard this, and I believe it" or "this agrees with my opinion, even if it may be just an opinion also", rather than saying "It's a statistic, and numbers don't lie".

Of course numbers don't lie. People do. Usually with numbers. :) Hmm... now where did that soapbox come from, and why am I standing on it...? grin