I'm not sure that's quite it...well first off, I have to say I don't think there are actually a great number of Pixar "haters". The majority of people will tell you that Pixar is a terrific studio. But are some of those people a little cautious about the latest crop of Pixar-themed attractions? Definitely. It's not because they hate change or Pixar, it's because there's a concern out there that Pixar films have just become the go-to overlay for a lot of recent attractions...to the point, many believe, that it almost seems like Disney is just cashing in on the hippest new movies.
Do I think that's justified? Not exactly, because the parks have always done that, and certainly Pixar rides aren't the only ones going up these days. But when you suddenly have a number of high-profile Pixar additions popping up at the same time across the parks, it does give the impression that Disney isn't digging into their idea well as deep as they could be. Pixar makes excellent films, and there are some fantastic Pixar attractions...but when Disney does something like a Nemo overlay for the Living Seas simply because Nemo is a cute fish that everyone loves, it makes you wonder how appropriate or necessary every application of the Pixar name is.
(For the record I really enjoyed myself at The Seas--moreso than I did when Seabase Alpha was at its deadest two years previous--but it wasn't much more than a fun time. The dark ride was cute and well-made, but out of place. It was clear that the kids really enjoyed seeing Nemo, as did I...but that Nemo appeal is all the more reason I think the attraction could have been pushed further than it went. Disney's got a great property in Nemo and has the potential to use the characters to really inspire kids, but the pavilion overall did little to inspire me like Seabase Alpha used to. There was just kid-friendly information about fish--nothing I couldn't find at a local aquarium.)