I wonder why he made this decision after launching. The consequences and economics of ad-blocking are nothing new or surprising, and I'm sure he knew this while developing the app. Sounds like he was threatened or blackmailed.
Seems like the type of extension that is in fact very popular, rather than some niche one that only a few thousand out of millions of people would use.
It's one thing to know you're hurting somebody's livelihood in the abstract, it's another to have them specifically call you out over it.