To preface, this is strictly an etymology question. I'm not trying to parrot the moronic conservative talking point "I'm not homophobic, I'm not 'scared' of gay people," or anything similar to that.
I'm genuinely curious about when and why the term "phobia," which originates from the Greek word "phóbos" meaning "fear" or "panic" and whose primary usage (as a suffix) in English was primarily used to describe intense, often irrational, fears of various things. Like an irrational fear of spiders being arachnophobia or an irrational fear of deep open water being thalassophobia. All of these words derived from the phobia suffix follow along with the original Greek meaning of describing an intense fear.
However, in modern times many words have the phobia suffix tacked on to describe intense aversion to or hatred of something (I'll just use "aversion" for brevity from here on out) rather than the fear of that thing. The obvious examples are homophobia, the aversion towards homosexual people, Islamophobia, the aversion of Islamic people, etc. From a purely etymology standpoint, these words with the phobia suffix don't quite seem to make sense.
There are even other uses of the phobia suffix that aren't refering to fear, strictly speaking. The most obvious examples that I can think of are hydophobic and lipophobic to describe materials that repel water or oil, respectively. These make a bit more sense to me than the others, since ascribing any sort of emotional reaction to chemical substances is a bit silly regardless, and I suppose a substance repelling another substance could be interpreted as "fear" but even in this case I think a prefix or suffix meaning "aversion to" would still be more apt.
Which brings me to my sort of second question. We have other Greek prefixes and suffixes that can precisely describe this feeling of aversion, in fact, we already commonly use them in other words. The prefix "miso-", derived from the Greek word "misos" already perfectly describes such a feeling and we have other words to prove it. Misogyny, misandry, misanthropy all describe the aversion towards women, men, or people in general, and there are plenty of other words that follow the same pattern of expressing aversion, not fear, of something.
Likewise, the similarly derived suffix "-misia" accomplishes the same thing by denoting an aversion, not a fear. So terms like homophobia could instead be replaced by homomisia which clearly describes the fact that they have feelings of hatred and not fear.
I'm not advocating that society drops all previous usage of these "-phobic" words and replaces their usage with "miso-" or "-misia" words. Instead, I'm more curious why the words that we *do* use developed along this route instead of the other aforementioned routes, especially since there were already existing examples of words and prefixes/suffixes that better described these beliefs and attitude as aversion or hatred rather than fear.
Edits: Fixing typos.