First of all, logically debating Ann Coulter is like playing chess with a tapeworm. The only acceptable way to deal with jokers like Coulter is either to ignore her, or to mock her viciously. Raj did exactly the right thing. He did not physically assault or intimidate Coulter; he just replied to her nonsensical, vacuous noise with more nonsensical, vacuous noise. Any sensible conservative must believe that Coulter is an embarrassment to the right, and deserves exactly what she got. And anybody who says something like "If only you infantile leftists would behave nicely, Ann Coulter would engage in a civil, grownup debate with you!" must be dropping massive amounts of acid.
Second, Raj's question actually has a certain logic to it (a logic which is, of course, utterly superfluous, but nevertheless if you're going to embarrass somebody then logic does lend your gesture a certain extra panache). It is common for "respectable", "centrist" conservatives (e.g., Massachusetts governor Mitt Romney) to say that gay marriage should not be legally recognized because (1) marriage is inextricably linked to procreation and child-rearing, and (2) we don't know what possibly-damaging psychological effects gay parents have on children. Note that both of these facts, and not just the second, must be true in order for this argument to work: if marriage and child-rearing are separable issues, then it shouldn't matter what effects gay parents have on children, as it's logically possible to permit gay marriage but ban gay parenting. Now, in marriages wherein the husband and wife engage exclusively in non-procreative sex, marriage and child-rearing are not, in fact, inextricably linked. So unless Mitt Romney and his ilk are ready to condemn anal-sex-only straight marriages, their argument for banning gay marriage is unsound.
Of course, Romney and others are never going to come out against non-procreative straight marriages, because straight conservatives only think that it's okay to invade gay people's bedrooms.