The back and forth

Do you talk to people about politics? At parties? At work? On the street? Some people say that's rude. That we shouldn't do that.
But ... well - I get that it can be rude -  or could be - or can be inappropriate (for instance probably best to avoid politics at "the Holiday Table" unless you're completely confident in everyone's ability to keep chewing and swallowing. But - other than that, must it always be "rude"? Or is it, maybe, sometimes, warranted. Necessary. Productive. Good.
Since our lives are directly affected by politics, shouldn't we at least, you know, understand what each other thinks is going on? And try to get a handle on what might actually be going on? As well as call our congress people, sign petitions, go to protests, vote, call them on their bullshit, applaud their progress and hold their feet to the fire to keep it up? Isn't that our job as citizens?
After all, what do we gain from keeping our mouths shut? Peace and quiet? At least the illusion of it?
Because when people who disagree about politics (or religion, or both) start talking, they often start shouting, and sometimes shooting (small scale - "man shoots in direction of brother-in-law, accidentally wounding second cousin and two nephews - or grand scale - terrorist attacks, full out war). Here's the thing. I don't want to cause an accidental shooting or start a war, but talking about politics is actually one of my favorite things to do. Most people, I know, would rather stick their head into a ceiling fan but not me.  Seriously - when I find another person at a party, at work, in a cab, who actually likes talking politics? (whether they agree with me OR NOT) I'm happy as a clam at a cancelled clambake.
I had a friend recently say to me that he'd stopped talking about politics entirely, unless he was certain the people he was speaking with agreed with him. He said he regretted letting some of his friends know how he felt about things, as they'd stopped being his friends now. 
He felt that sharing his feelings was bad, and that losing these "friends" was bad. But what kind of loser friends could they have been in the first place if that's all it took to get rid of them? Finding out that he did indeed, believe in global warming, gun control, etc and so forth, and therefore, that people who didn't might be, you know, stupid. 
Though I doubt he actually called them stupid, maybe they just felt stupid (because not believing in global warming and gun control is, you know, stupid). Whatever - bad friends, good riddance. The end. 
I've had awesome to really good to perfectly fine discussions with cab drivers - fellow party guests, co-workers and strangers on the street about politics. And sometimes it's not so good. And I wish I'd not done it. But I never truly regret it. It's always a horse I feel is worth getting on again, even when said horse calls me an elitist asthete communist socialist Jezebel and throws me across the virtual room. I mean -- I love preaching to the choir, you know? They're so receptive. But sometimes it's worth it to preach to "not the choir". Or talk to them rather. And listen to them. Even if it makes you want to pull your hair out. And if you're patient and leave your hair where it is - then sometimes there can be an interesting exchange of ideas, or unexpected common ground. And if not? At least you tried. And learned something. (like how to better pick your battles - and maybe how to get out of them better once you've picked them).