I have worked with both openly gay and lesbian people. I agree that it's somehow more obvious with men. More often than not, it's easyto tell that a man is gay. On the other hand, I was working in this place for about four months before I knew that two of the women there were in an LTR together.
As a result, I have noticed that gay men seem to get more prejudice than lesbian woman do. I've seen a gay couple beaten up for being gay, and one of the other men I worked with got punched in the face for trying to shake a straight man's hand (he was told to get his "filthy" gay hands away from him and threw a punch). It's dusgusting. And yet, I have had several friends who've been gay and they have never displayed any general dislike towards all straight men in return. Likewise, they will often have a number of female friends.
The only prejudism I've seen towards lesbian women is the baffling belief that they can be "turned" if a sufficiently manly man brute makes his attempt, as if they are merely claiming they are lesbian because they have never met said sufficiently manly brute
.
As for this not seeing it as real, I've never come across this. But I think I can guess were it comes from. Of the lesbian couple I worked with, one of them once was straight, and changed because of an abusive relationship. Whether this applies to others, I do not know, but she explained that she, like many others, can chose which to be with, and chose a woman because she felt safer. Perhaps this is where this attitude comes from? I don't know.