Elon went after Apple saying Apple's walled garden is stupid and that Tesla would never do that...all while Tesla is building a walled garden themselves.
I'm not going to fault Tesla though. The Supercharging network is the only advantage they have left. Why would they want to give that up and not be able to gain access to people's emails and phone numbers when they sign up through the app?
On one hand, Tesla gets more sales because of their supercharger network. On the other hand, there's been more scrutiny and regulations regarding fragmentation of standards (e.g lightning vs USB-C) and if Tesla were to be forced to open up by regulation (not saying this will happen, only speculating it's possible, disregarding likelihood) then accepting incentives with it would be better than not getting anything.
Also, now that they've had incentives on the table and that can signal more value in the charging network. Could be trying to get better incentives? Again, all speculation based on simple observations, who knows.