By “dropped,” he means announced:
The fun thing about FTC actions is that you can immediately figure out who the bad actors are by looking at the markets. This is Planet Fitness's stock, you might be able to figure out when the FTC dropped its rule making it as easy to cancel a subscription as to sign up for one: pic.twitter.com/D1ckp5BlvQ
— David Dayen (@ddayen) October 17, 2024

Hahahahaha. That’s amazing.
I agree that it was an important and good action by the FTC. But look at the axis on the right. An $80- stock dropped by $ 1.50. Yes, it may very likely be due to the news. I’m no particular fan of PF, but c’mon now – that’s called “a normal day for a normal stock”.