Tons of people all over the world love the taste of chocolate. But there will always be people that really don't like it but maybe they'll try it again and think ''Maybe if I try another brand/give it another shot I'll like it."

I highly doubt that a preference excluding sex is a mental disorder. It's just simply a preference. No two people are exactly the same and even if it seems everyone in the entire world enjoys a specific thing, there is more than one person that hates that thing. It might not be a common occurrence, but it's definitely a normal one. What you said about oral, some people may hate chocolate but those same people may like chocolate cake- if I'm not confusing you too much. Sorry, I like using examples like that.