I doubt this doesn't happen way before. It's just more apparent now that Social Media is huge. People are petty and having a taste of the internet just enables them. I mean for example internet shitposting was a thing in forums way before friendster, myspace, or whatever social media outlet. Fast forward, now everyone has their own space to shitpost and what's worse is that it's harder to get away from it.

maybe he isnt a good friend?

I'm talking exactly what you're talking about. A person doesn't have to have a certain label to be deemed as evil or unrighteous. There are lots of unrighteous people supporting both Clinton and Trump. To think otherwise is at least ignorant if not close-minded. If you think you are any better by voting for Clinton and not for Trump ( and this also goes for Trump supporters who feel the same towards Clinton supporters), you are no better than the people who you are judging.

To be a friend of mine, one must meet a certain ethical standard. The reich-wing is certainly below that level. If it turns out a friend of mine values authoritarian hatred, then you bet I'm going to reconsider associating myself with that person. There are plenty of far right political views that have no place in the world, let alone a place in my social life.

https://www.youtube.com/watch?v=luJJBeCFeM0

The problem is stuff like that tends to get jumbled by subjectiveness and the fact that if that truly permeated their personality, you wouldn't have been their friend in the first place. The implied message here is a friend of your has different political views that didn't impede your friendship, but now you're presented with the choice of remaining their friend because they're the same person they were yesterday, or being a petty lump and disavowing their friendship.

Oh god... That's... That's just awful D:

Seriously, I think you may have blown a speaker with that, dude. Jesus.

I've blocked people on Facebook before for posting non-stop political stuff. Just not interested in seeing that kind of thing in my feed. I used the site to keep in contact with old friends, not listen to the kid that sat three seats behind me in concert band explain why [Insert Politician Here] is the Second Coming of Christ.

I've also blocked people for posting daily pictures of their beard growing in November. Actually that's probably happening now. Time to re-block people.

Awful you say? :D Then I challenge you to watch the extremelly realistic music video. Bwahahahahahahaha! It's gaming related and everything.

https://www.youtube.com/watch?v=fPslvBVqJp8

On the topic of blocking people, I believe the only petty blocks I've done are against people who trash-talked Pokemon GO. Fine if you don't like it, but it got fatties out of the house.