I think the whole percentage of sexuality is bs. It is just a finer way of labeling, without saying gay, bi, or straight. There is such a spectrum, and a sliding one at that, that even if you lump yourself into a group there are times when life happens, placing you outside that for a moment or two.
Leading into the discussion on people who identify as straight letting a same sex person give them a handjob. From personal experience, I know a lot of people who allow that, and I have done that. It isn't anything new. People are just talking more openly about it now, because the internet gives a nice safety barrier for anonymity.
There is a laundry list of why someone would allow that, and why it doesn't affect their life afterwards, or their sexual identity. It boils down to situational horniness, if you cut all the fluff out.
So, no, they aren't lying. It is just a thing some people do, and there is nothing wrong with it.