No, it isn't. That's an ignorant viewpoint since you don't know how straight people or asexuals think or how we have always felt. Flies in the face of science too.
I don't disbelieve any. If somebody told me they were attracted to a tree I'd believe them. Not that I'd be into that, but that doesn't mean I'm going to say it doesn't exist Why does everyone always have to be questioning everybody else. Does it really matter in the end.
In most cases, it's just like a way to seek attention in my opinion.
In most cases means not all the time. So that means there are times where you think they are being genuine and aren't just seeking attention. The question isn't Do you believe people when they say they are a certain sexuality, it's do you think the sexuality exists at all.
I didn't know gays were this ignorant
Anyway it dosn't matter what you believe people are a, gay, straight or bi.
Whether you believe it or not is ****ing irrelevant