From what MerakSpielman relates, I'd assume you're on the tail end of your relationship with these people anyway. I'd find out the reason behind the rudeness of the emails at some point.
The first thing I'd look at is: have there been any personal conflicts because of your differing views? If you have nothing to do with them socially outside of the game, that's one thing. Not really unusual after 3 years, esp. with young kids involved. If there have been no real conflicts, I might consider staying if the alternative was no gaming at all. I'd start looking around, though.
Think of it as a job you're neutral about: you have it and it's OK. It pays the bills, you have no significant personal conflicts... but you want more. Look around, interview, go up and see the place and people, etc. If you find a better job, give some notice, tie up loose ends, cut the strings and never look back.
We've got six people in the current game: two of us skew far to the left, one skews mid-Right, one is Moderate, and the two new people are basically unknowns pollitically and religiously but younger than anyone else: they seem to skew Left more often than not. We have one Buddist, one Atheist, one lapsed Baptist, one middle-of-the-road quasi-Agnostic. Most of us have been gaming together for 15-20 years on and off (more on than off) and we interact socially outside the game (go to the movies, eat dinner, go to the theater, etc); we're starting to integrate the two new people into that social circle to some degree as we get to know them better. We've known one about a year, one about six months; they work together.
We have four married people (none of the spouses play), two singles. One has a teenaged child who can look after herself; the other couples are childless.
For the most part, we just follow the standard dinner time rule of no politics or religion at the table (maybe that's just a Southern politeness thing?), though sometimes we get into those areas. Usually if we talk off game, we talk about work, what movies we want to see, what cool gaming Stuff we might want to pick up, various hobbies, personal stories. On some things, we just agree to disagree. We lay down that stick and don't pick it back up again.