Tell me is the anti-SSM tolerant of gay marriage? I would say No, they aren't. Is the pro-SSM tolerant of the view of anti-SSM? I would say no, they aren't.
Now, there is the level of intolerance involved as well. Am I intolerant of the view that SSM should be banned to the point I want to make that viewpoint ILLEGAL? No, I'm not. Would I be intolerant to the point I won't have them as my friend if they hold a anti-SSM belief? Absolutely. Just like I wouldn't be friends with someone who hated black people or held the view that interracial marriage should be illegal.
Americans are so enamored of equality that they would rather be equal in slavery than unequal in freedom.
Alexis de Tocqueville