The people in the camps were undesirables. Most were immigrants, some were homosexuals and some were dissidents. V obviously wasn't an immigrant, so that means he was a homosexual. He didn't claim to be political before he was taken to the camps, so that means he was a homosexual.

In the book, Evey has an affair with the guy she runs to (I forget his name) when she escapes V the first time. In the movie, that character is portrayed as gay and V is portrayed as in love with Evey. That never comes across in the book.

I liked the book, but the stuff that was changed in the movie IMO would be unfilmable, and therefore it improved the pacing of the story. that in mind, I really, really enjoyed the movie.