You are aware of the Log Cabin Republicans
right? Sure the Republicans play to their strengths, Dems do too. No doubt there's a lot of "closeted" Democrats in Congress that are very homophobic. Strange they've not been overwhelmingly supportive of Gay rights issues of late.
Like Kerry in the last election, or Gore before that. They all play to whatever they think will bring the most votes and keep them out of negative headlines. The fact that congressional leaders wanted to keep Foley out of the headlines is a no-brainer, and the Dems would have done the same thing.
But the standard of "child" here has been abused black and blue. Gay rights organizations have been pushing for lower ages of consent all over the world. It was partially due to their efforts that what Foley did wasn't illegal enough to do anything about.
Are you really so naive to think that had the Republicans purged themselves of Foley they wouldn't have made that about homophobia? You can bet the pages wouldn't have been "children" then. They would have been 'young adults' and while Dems would have agreed with punishing the sexual harassment the main point of fire would have been that they just drummed him out for being gay.