The scale of the disrespect makes it impossible to equate what atheists do with what theists do. I mean, a disrespectful atheist mocks religion (and, in my experience anyway, everything else). A disrespectful theist passes laws making me less than a second-class citizen. Or, you know, murders me. Or threatens my wife (it's happened). There's a BIT of a difference there.
Math is a language, and as such is the product of our minds. God is supposed to be an omnipotent external force, typically with a personality. So this doesn't usually work.
No, it doesn't justify it. However, what you have to understand (and most don't) is that theists demand respect AND the right to DEFINE THE TERM. Meaning, what they consider respectful is the ONLY concern--the opinions of atheists are irrelevant. It's a blatant attempt to dictate the terms of the discussion to atheists.
See, to a scientist taking the time to evaluate an idea is showing it respect. We may come to a different conclusion, and most scientists will argue anyway, but we've at least given it thought. Truly insane ideas (look at any Creationist website to see examples) simply get dismissed. So writing The God Delusion was a sign of respect from Dawkins, for example: Your ideas are worth looking into. To theists, however, ANY questioning of their beliefs is disrespectful. You're not allowed to look at it--you just have to accept it. Most of the time this doesn't matter, but theists try to give their views the force of law. I mentioned Blue Laws (if you're not familiar, they're laws forbidding the sale of alcohol on Sunday, and in some cases forcing businesses to be closed on Sundays--a flagrant example of Christians dictating their faith to non-Christians) and laws outlawing atheists in office (which means we're taxed with no representation, which is sort of a major issue in the USA). Forcing us to teach Creationism (ID is creationism in a cheap suit) is another example. To oppose any of these ideas is considered by theists to be disrespectful--despite the fact that they are obviously disrespectful to EVERY OTHER FAITH ON EARTH.
Theists have a twisted view of respect, and try to force it down our throats. Atheists refuse to swallow it, and theists scream and howl that we're being disrespectful for simply stating our beliefs.