Why isn't it "homodium" instead of "homophobia"?

pho·bi·a /ˈfōbēə/ an extreme or irrational fear of or aversion to something.

As it happens, OP, 'phobia' 𝑖𝑠 accurate; straights (mostly Christians) are terrified of homosexuality, for all sorts of reasons. For one thing, they often claim that God afflicts nations with misfortune and natural disasters (floods, hurricanes, etc) for tolerating LGBTs. For another, they're terrified that homosexuality is catching, that their kids are susceptible to being converted. They believe that homosexuals carry communicable diseases. And last but not least would be those who exhibit the most obsession with homosexuality, drawn to the subject again and again, who feel the need to seek it out and condemn it. These often have secret same-sex urges which they can barely keep under control, and this terrifies them most of all.

Because I would get that confused with my Imodium, and you don’t want to see what happens without it.

Wouldn't it have to be "misohomophilia" or "misarsenokoity" or something like this?

R4 Isn’t misohemophilia that disease that the ambulance chasing lawyers are always trying to recruit people for a class action lawsuit?

Linguistic problems abound here.

First, "homosexual" and "heterosexual" -- like "television" -- are words built by mixing Greek and Latin stems, ordinarily a linguistic no-no.

The word "homophobia" is built entirely from Greek stems but doesn't make "sense" in those terms, since it includes no stem about sex or gender. Literally, "homophobia" means "fear of the same."

"Homodium" is a linguistic non-starter -- "odium" is from Latin, and in any case there's already a Greek stem ("mis-") for hate. But smashing that into the "homo" stem isn't going to fix anything.

thank you R6 for being an intelligent human

Homodium is what stops you from pooping silly.