Can confirm. I had an older coworker come out to me by saying that her husband "never judged her for having girlfriends in the past", but didn't know the language around it. She was treated so poorly by so many people that she didn't feel like a part of the gay community, moreso ashamed and judged. She couldn't talk to people about it, so when would she have learned those words?

Sometimes it takes someone younger being open about it for the older generation to even realize that there are words for it now.

I remember during the AIDS crisis health workers starteed to use the phrase "Men who have Sex with Men" in their education outreach partly because a significant number of these men did not self-identify as gay or bi.