Perhaps I don't understand some of either `高階の関数を知っているなら` or `と思っておけばいい` maybe this is a grammar point I've not picked up on. 
But I can't see where the idea `is disliked recently` comes from.
Either way, `is disliked recently` sounds unnatural. Something that conveys the same meaning as `is disliked recently` but sounds more natural would be `has fallen out of favour recently`.