The leading gay money group did ask all the leading Republicans to attend a debate on gay issues:
The Foundation's first ground rule was that we needed to get confirmations from at least two of the top three candidates on either side before we'd proceed with any forum. On the GOP side, Mitt Romney said no - and we never heard back from Rudy Giuliani or John McCain. That's right: no response. Furthermore, not a single one of the Republican presidential candidates thought it was important for them to return HRC's questionnaire. Without any responses from any of the top three Republicans, there would obviously be no GOP debate.
HRC should not be immune from criticism of its partisanship. Their decision to all but merge with the Democrats is unfortunate - but they're not the ones fundamentally at fault here. The Republican party establishment really does exhibit contempt for gay voters. I know of no other group that doesn't even merit a response or an issue on which so many Republicans have so little to say and staggering levels of ignorance, as was revealed in the South Carolina debate.