I agree with you very much on all points.
I personally think that it is fine to appreciate Jason as a supporting aspect to other characters and the general Batmythos. I personally appreciate what Jason's death and what it meant to the Batfamily. I also appreciated his return as someone who represented a failing of Batman's morals. I prefer him to have an antagonistic relationship with the Batfamily. I think that it is a more interesting direction both for him an the other characters involved.
Does this mean that I don't appreciate him? No. I appreciate a different version of Jason Todd and that's perfectly acceptable. Even if you believe that this opinion is on the built on the basis of making Jason a plot device to other characters, that doesn't mean that its not appreciation. There are appreciation threads for the Penguin and Kite-Man on here and I am certain that nobody sees them the same way that anybody here views a character like Dick Grayson for example.
There are different levels and different kinds of appreciation. But they are all valid.