I don't particularly care for Pixar movies (I prefer traditional animation over the CGI stuff that Pixar does), so I haven't seen nearly enough of them to know if that guy is full of it or not. It wouldn't surprise me if it's true though, it's not the first time that something like that has been done.
I don't think that reverance or respect for the dead needs the dead to be hidden from sight completely. It is the attitude that you bring, as a witness to a dead body, that matters, not the display and witnessing of a dead body, per se.
But her love for Sully is, after all, the crux of the entire Pixar universe. The love of different people of different ages and even different species finding ways to live on Earth without destroying it because of a lust for energy. And that is the Pixar Theory.