I work as an artist/animator at a game company.
The games industry has about as many LGBT people as the general population. I know there are some gay gaming professional networks, I might have joined a few but totally forgot about it because its a scene I'm not very active in. I don't think its an industry with a "gay mafia" or anything like that.
The number of queer people I work with really ebbs and flows. At one point my team was almost entirely gay men, now there are only two (self included) on my team. I'd also speculate that currently there are more LGBTQ people at my studio who are "professionally closeted" than there are who are more open about their sexuality. (Sorry I can't think of a better way to word that.)