There's no existing black market of criminals extorting politicians and celebrities over Youtube comments (also how you go from an email address to an identity is itself iffy).

You are imagining a potential market, the exploits are priced against markets that are real and pay out today. Security researchers aren't traveling salesmen going around to every shady character on the internet and pitching them on the potential of a new criminal enterprise.

And so what's going to happen? Are there blackmailing rings that are in active need of ways of tying youtube comments to work accounts that are paying out the nose?