I've seen outrage about PFAS, eg the recent rainwater isn't safe to drink according to the EPA articles. There's also been many campaigns over the years about various chemical additives, eg BPA. You've also got lots of people rallying against user/overuse of pesticides and herbicides. I'd wager it's less that the Sacklers are an easy target (as shown by the continued lack of any consequences), but more that it's a slow build up of anger over the continued abuse of people for profit.

Also, people are not stupid for trusting doctors. Are you not supposed to listen to professionals with usually more than a decade more of education in a specific field than you?