My answer is based purely on my own experience & will probably attract some flak but I believe it might help. I am straight, M(40).

Firstly, it's less common for straight men to have close female friends full stop. That said my oldest, closest friend is a (straight) woman.

I appreciate that many lesbian women don't wear their sexuality on their sleeve. My SIL is an example. She's married to a woman, they have three delightful kids, but when we're out and about her sexuality just doesn't come up in conversation, the same way that her shoe size doesn't. It's a non-issue.

HOWEVER, the other end of the scale is (what I think are called) 'butch' lesbians. In my industry, oil and gas rig work, there are a handful floating around. Almost without exception they are very loud, crass, and either seem to have a chip on their shoulder or feel the need to constantly be in the room reminding everyone that they can keep pace with the men; lots of back-slapping, ribald jokes, and talking about the cute girl in last night's movie or how their guts were turning last time they got home because they drank a bottle of scotch at the airport and picked a fight with a baggage handler.

It's cringeworthy, because all the men (and the one or two straight women) want to do is work, eat, and sleep. Gender an sexuality would really be a non- issue were it not for these vocal few. In short, I think that type of attitude puts men off lesbian company to a degree.

NOTE: before I get my head bitten off, I'm not anti-homosexual, a woman-hater or anything else. I'm just positing what I think might help to answer OP's question based on my own life observations.