The point of a petition is to get a lot of people to sign, so I'm not shocked that someone who felt strongly enough to sign a petition on the topic in the first place chose to share it, y'know?
I definitely have experienced what you're saying about Facebook shedding light on how others may feel about topics you had no idea they even had an opinion on. I know my mother and her siblings are very conservative. They choose to call me a Democrat to fuck with me, regardless of how many times I say I'm a moderate. Anyways, I've grown up in this environment, I'm used to fighting politics with them, no matter now many times I tell them I HATE talking about politics. I believe that we are put on earth to live a life, we're influenced on All sides by what is right and what is wrong, and we have to choose what to believe. I also believe at the end God will judge us, and I definitely believe he's the only one allowed to. Our souls anyways. I got off on a tangent there, the point is, I can't say with any real certainty what the right thing is on every topic, so I try to live the way I think I'm supposed to, I try to impart how I feel when given the opportunity, and I plan to try and raise my children to look at life in a similar manner. What I'm getting at is, this is the argument I have with my one aunt in particular almost every week. Meanwhile, the children of my other aunt, I always thought they were really liberal in their beliefs, but then when they got on Facebook and starting posting this, that, or the other thing, I was shocked to see that they're just about as conservative as she is. I don't respect them any less, but it certainly caught me off guard.
one of those cousins married a guy who is kind of like the relative you're talking about. He was really awful to just about everyone, family members included. He once Facebook wall attacked the daughter of the aunt who argues with me weekly because she's a fan of Twilight, and vampires are apparently Satan's minions or something. It was bad. However, I have definitely noticed in the last few months-year he's really mellowed out. I can't promise the same will happen in your situation, but you never know.
I DID notice as recently as two years ago an intense amount of Happy holidays only tenseness, but maybe it was pretty isolated to the states only. I think it must have hit a fever pitch that year or something, because I felt a remarkable amount of relief last Christmas when it first dawned on me that I was hearing little to nothing from the happy holidays side of the fight. To the point that whenever the Merry Christmas people were raising their voices, I actual grew angry with them, which, surprise surprise would be the "side" I'd normally be on, were I one to be bored enough to fight the war against Christmas.
No, I haven't relistened yet, yesterday was a Tad hectic. I will try this afternoon whenever I wake up.