A little investigation and you would have found that Princess is the least wheelchair friendly cruise line. They do not allow wheelchairs to tender at tender ports and in lieu of being first in lines wheelchairs are actually last (including debark). I suspect you were used to something else and then were surprised that Princess did it differently.
BTW--I'm not saying Princess is wrong in their wheelchair priorities, in fact truthfully they are following long standing sailing traditions, not the political correctness more common on most other cruise lines. In the event of a disaster wheelchairs would block passageways and escape routes for other passengers trying to escape thus possibly increasing casualties by a large number.
Princess is also the only cruise line to honestly tell you at muster drills what to do if the ship is sinking very quickly.
I think they just have a more honest and realistic approach.