Why "This is in bad taste"? I think must be "This is a bad taste". Is "in bad taste" the idiom?
Yes, "in bad taste" is an idiom meaning, roughly, uncivilized or showing bad manners. "A bad taste" would literally mean a nasty flavor on the tongue.
so the sentence roughly means "this is tasteless." as opposed to "this tastes bad." ?
An answer "This taste is bad" seems to be wrong. But boesn't "This is bad taste" require an "a" before "bad"?
This was my thought too, regarding the article. As for "this taste is bad" it would've been "Цей смак поганий."
This taste is bad