I thought it was a lovely scene. It was nice subtle reference to Children of Earth and The Doctor helping Jack through the pain. So what if it's two guys?
Exactly.
And if I had kids and they asked about that scene, I'd just explain to them that some men fall in love with other men and some women fall in love with other women, and Jack and Alonso are men who fall in love with other men.
And, lest the bigots out there object, no, that's not the sort of line of questioning that's inevitably going to lead to explicit descriptions of anal sex any more than explaining that men and women fall in love always leads to explicit descriptions of the missionary position.