A foam is just another texture of a sauce as a garnish, and typically not the main sauce. It’s not as “why was that even food” as people put on. It’s just an easy scapegoat for something different.
Cotton candy is air fluff that melts instantly on your tongue and leaves a bubblegum or artificial cherry taste behind. A foam is a similar thing, just with basil or truffle to compliment a piece of lamb sauced with its jus.
It’s just lazy commentary.
I might get flagged for spamming this same response everywhere, but snow cone backwards all day, Alex.