Yes you should. Fantasy humanoids should jump higher than irl humans.
Why? Oh, and simply saying "because it's fantasy" is circular reasoning.
And if a guy who is 1.81 meters high can jump 2.40 meters high over a stick, why shouldn't a beasty cat be able to jump higher?
If you were paying attention to what I said in my post, then you'd realize I wasn't arguing against this. I think Khajiit should be able to jump higher than other races. It should be one of their racial abilities, because their joint structure is different from a man or mer's.
EDIT: Correction; should be different.