• That unless homosexuality is severely punished, everyone will suddenly go gay. These people imagine others, like themselves, are fighting back their gay impulses. St. Paul subscribed to the prairie fire view of homosexuality, that unless it were suppressed, everyone would prefer it.
• That homosexuality will become compulsory for all if gay people are given civil rights. Again this is sort of rape fantasy. The afflicted fantasise about being forced to have gay sex, but of course it would not be their fault, then.
• That failure to properly persecute gays will result in a plague of child molestation. Again the afflicted imagine others are suppressing desires to molest children just as they are. They project it onto gays. In reality, the person most likely to molest a child is her father. Gay men are less likely to molest children than straights, for the obvious reason, children are similar to women (small, high pitched voices, unmuscular, submissive) not to men.
• That gay men will make passes at them. This is so ridiculous, particularly when the homophobe is fat and middle aged. They flatter themselves. There are body language mating rituals, and unless you give back the appropriate signs, others will assume you are not interested.
• That gay men will convert them. It is impossible to change someone from straight to gay or vice versa. There are plenty of gay men already. Nobody is interested in trying to create more. Again this is a fantasy the homophobes have that they are ravishingly desirable.

"The lady doth protest too much, methinks."
~ William Shakespear Hamlet Act III scene ii