Gotta say, it kinda sounds like you are taking it personally.
It was a personal statement directed at me, so of course! I am more amused than anything, and a bit annoyed that just because I don't want to date my friend, all of a sudden my sexuality is being questioned, even if perhaps jokingly.
Spin the situation on its head and imagine my mom calling my friend a lesbian because she doesn't want to date me, and just wants to be friends. That wouldn't be cool either! I'd tell my mom what's what. "This isn't the 60s anymore mom, you can't say crap like that about my friends"
I'm such a n00b homosexual though, I can't even do the lisp and I'm horrible at fashion. I don't even like penis. None of the stereotypes seem to apply to me, I don't think I'll ever be accepted.
So not dating anyone makes you gay? I'm really really gay then.
Probably a good thing we didn't end up on a boat in the arctic together. Imagine how awkward that would be if we both realized we're gay at the same time.
Seriously, though, why don't you want people's moms thinking you're gay? What difference does it make to you? And what difference does it make how it came about?
Are you worried that your reputation for being gay will somehow cramp your style with potential bedfellows in the future?
The thing with most people's moms is that they grew up in a different time. A time when "you're gay" was an insult and not just a fact.
Her mom was essentially saying: "What is wrong with him?"
I haven't had a girlfriend in a while, I don't really date. I'm happy where I am. Her mom is implying that I'm not a "normal heterosexual male" because I'm not jumping at the chance to insert my penis into a vagina at the first possible chance of an opening.
It's a bit sexist, yes? As such I'm going to take the situation, flip it around, and mock it.