Maine is a state where almost half the households have guns. I don't think opponents of the second amendment are going to find a lot of support there even after yesterday's mass shooting.
Like most things fox news has turned the entire debate into an us vs them thing. Gun control is surprisingly something that most Republicans and Democrats agree on.
People advocating for gun control aren't necessarily opponents of the 2nd amendment, but people talking about well-regulated militias usually are. What's the point of bringing up that strange phrase unless you don't think that the 2nd amendment's right to bear arms applies to everyone regardless of membership in some sort of militia?
That's not an unreasonable reading of the text, but if you're going to look at the Constitution that way, you'll see that it doesn't talk about abortion or gay marriage either. I'm in favor of abortion rights and gay marriage, and that's why I don't start "but the Constitution doesn't literally say..." arguments with conservatives.