It’s tough because people understand gay and people understand straight, but people don’t “get” that you might be turned on by certain things and not others or that interest in a gender might be purely sexual.
It’s easy to stay closeted because coming out as bi is way more complicated than it’s worth, or than it seems to be worth. Few close to me know and an ex who knew would often tease me about it. I am bi, but I guess I’m pretty well in the closet about it. I can sympathize with the “straight” guys.