"People like fish."
Translation:Ludzie lubią ryby.
Maybe simply because you also rather say "People are strange" than "Persons are strange"?
I wouldn't use "osoby" in such a general sentence. If it was a bit more specified, like saying "three people", then "trzy osoby" is the way to go (yes, "osoby" are more probable than "ludzie" when you use a numeral, probably just because of grammar - "ludzie" need a collective numeral and that makes it more complicated). Or "people who voted for Scooby Doo" could also use "osoby". But I wouldn't say it here.
Yes, "ludzie" is masculine personal, but that has nothing to do with the fish. It matters for the words (pronouns, adjectives) that describe the noun "ludzie", e.g. for the way to translate "these people" or "tall people".
The translation for the object of the sentence, "fish", will be the same in "Women like fish", "People like fish", "Cats like fish" and every other sentence which uses "XYZ like fish".