There is some sense in the "homophobes are gays" thing
Obviously it's not true in all cases, and I would say only a minority are actually full on gay. But many of them do have latent homosexual tendencies, which explains the insecurity/homophobia.
I can't be arsed looking, but there have been studies done on this, which backed it up iirc
Without bothering to debate whatever the supposed numbers are it amounts to a threat to smear anyone with a label they don't want over political/cultural differences. I suppose penis phobia might carry a stigma as well. Neither charge would seem to me to have much in the way of empirical evidence to back it up.
I think they're both pretty different
Suggesting a homophobic person is gay is playing on their own insecurities, and usually works in my experience. No one is 100% straight or 100% gay imo, so it's not unlikely that if someone';s being homophbic, it is because of their latent homosexuality. I doubt many people actually think that a homophobic person is therefore actually
gay. But to suggest they're insecure about their sexuality (which is what the whole thing is about really) is actually pretty fair
Suggesting gay people are just scared of men/women though is kinda rididculous though lol
I'm sure there are some who were abused and therefore think they're gay because they're uncomfortable around men/women, but that's gonna be a very small minority
Also the "are you gay" response to homophobes is a reaction to their bigotry. "you're scared of penis/vagina" to gays is bigtry in itself tho