Assuming any such comparison is valid is purely speculative. There are significant differences.
> anyone who reaches fluency in a foreign language just "magically" stops hating it.
Not true (plenty of people learn Mandarin and regret doing so), and even if it were true it could just be survivorship bias - of course people who hate a language are less likely to become fluent in it.
> Turns out they don't really hate the language, do they? They don't hate phonology, morphology, syntax - they "hate" the culture, the idioms, the orthogonal stuff, right?
No, sometimes people really do hate the language.
> nobody in the right mind would ever join a discussion only to say "I hate Spanish, it's weird and hard to read".
That might not be a productive thing to say in a discussion, but that doesn't mean it can't be true.
> Like I dunno, how could anyone hate recursion, or closures, or pattern matching, or parametric polymorphism - these are just ideas, specific tools to use in specific context and situation.
Plenty of people hate any or all of those things. I'd say it's reasonable to hate a tool that tends to have bad consequences - e.g. a language feature that makes code superficially easier to write but hard to refactor or debug.