"I have no gay friends," is perhaps an indicator of one of three things:

A middle aged person recently told me that he doesn't have any gay friends and has never had a gay friend or even a gay acquaintance.

I think this probably means one of three things:

1. He doesn't have many friends.
2. He's a bigot and his gay friends know it.
3. He's part of a frighteningly insular community where gay people exist but would be ostracized or worse if they ever revealed themselves.