I think the crowd on Reddit from the net neutrality days was a different one compared to the one now.
Reddit Was Fun
Memorial to "rif is fun for Reddit" Android app, aka "reddit is fun", shut down after June 30, 2023
Oh, no doubt. What's the net neutrality case for shutting down 3rd party apps?
Net neutrality and reddit's API changes are pretty different situations.
Losing net neutrality could have raised prices on the entire internet, but the important thing is ISPs have too much of a monopoly on internet infrastructure. Many consumers across America only have one or two options for their ISP.
Reddit and twitter's decisions to privatize their APIs isn't a new phenomenon. Other companies already do this for a variety of reasons. Reddit's worry about AI driving up their cost is valid, but instead of tackling the problem as a bot problem, they took an easier way out and damaged the user experience.
Where the situations are different is: it's accessible, cheap, and profitable to rebuild a site like Reddit and create competition. It's not any of those things to compete against an ISP.
The wording on your post makes it sound like supporting net neutrality is supporting the API changes, but that's not true. I can help give some clarification if you want.