This explanation is useless imo because it expects the reader to already understand the weirdest part:
"If I have a function A -> B, how could I possibly get something that goes in the direction F B -> F A out of it?"
The answer to this is: given e.g. a function that accepts a B, i.e. `B -> ...` you can compose it with `A -> B` on the _input side_, to get a function that accepts an A, i.e. `A -> B` (+) `B -> ...` = `A -> ...`.
Once you've managed to get that across, you can start talking about contravariant functors. But expecting people to just intuit that from the condensed type signature is pedagogical nonsense.
"If I have a function A -> B, how could I possibly get something that goes in the direction F B -> F A out of it?"
The answer to this is: given e.g. a function that accepts a B, i.e. `B -> ...` you can compose it with `A -> B` on the _input side_, to get a function that accepts an A, i.e. `A -> B` (+) `B -> ...` = `A -> ...`.
Once you've managed to get that across, you can start talking about contravariant functors. But expecting people to just intuit that from the condensed type signature is pedagogical nonsense.