LGBTQ at CambridgeWatch
There are quite a few LGBT people in Cambridge and the support is, on the whole, good.
Either people are more comfortable and feel more at ease with coming out, or there is some kind of soft correlation going on. I suspect it's probably both.
I don't think Cambridge is special in its (good) treatment/ attitude. You will probably find a similar level of support at a lot of top 10 Universities.