I understand what you mean, I don't vote because in my state of New Jersey, voting is pretty much useless here as well. Democratic candidate pretty much win the presidential election here by a landslide so it's pretty much pointless for me to go out there and cast yet another vote in the same direction. I have more important things to do in my life and cherish my free time after mentally exhausting hours of work. I can see how your roommate has gotten himself into his current situation, I have a feeling that he is an introvert as well so there isn't a high drive in his life to go out and meet people. At least he has you and maybe if you and your family is interested, inviting him on familial gatherings that you have since his own has more or less abandoned him.
A lot of people are very triggered by what happened with the Trump election and will lash out at anyone that doesn't appear to be doing what they can to get out and prevent it from happening. He doesn't understand the reality that the way our government is set up, a lot of people can't do much unless they divert a LOT of their time into politics, which I am not surprised many are against as they hate politics. Hell, politics has caused insane strife between family, loved ones, close friends in this election and that's a shame. Almost like bloodless civil war, very ugly, brother against brother, etc. A good friend of mine, his brother-in-law gets super triggered anytime Trump is mentioned and has broken off friendships with a lot of people who aren't raving anti-Trump people as well. Some people have enough to deal with in their own daily lives to focus a ton of energy on politics.