I have to wonder why gay rights groups don’t counter protest when these freaks are out there. Perhaps because it isn’t seen as a problem when someone from the armed forces is the target.
Or perhaps they don't want to make more of a spectacle than there already is. Or to lend credence to the notion that homosexuality is at all relevant to the Phelpsholes' protests at the funeral of soldiers or students.
I doubt that the families are asking the gay rights groups to be there. It makes more sense, and is better for everyone involved, for groups like the Patriot Guard riders to handle things (I haven't heard whether they're planning to go to Virginia Tech).
Whether you like or dislike gay rights groups, I think it's the right call for them to stay away, whether it's a matter of sensitivity or just a PR calculation.