I wouldnt say discussing dev/developing game process, and interactions with fan-base is off topic, or at least it shouldnt be.
Have you looked into famous games threads such as milky city, badmilkingsagga,...or badik, wvm and such?
There are many similar comments untouched, though the same "discussions" could be repeated more than once.
On the other hand you have some threads, such as CoBD, where on topic posts could be deleted on regular basis.
So i wouldnt say the posts being deleted as ot, or not, has to do mainly with it being truly ot, yet more with threads/bots included within.
In this case we shall see how it goes.
You are feeling strongly for this dev obviously, and you are defending him from "unfounded attacks" (and you even have used the famous argument "common, that just too low monthly pledge for milking"), and thats ok.
Similarly ok should be to express doubts regarding his work, and even more about his recent relation to the game, and his fans.
There is nothing OT there, both ways, imo.