I do not understand this position.
Leonin were in the Theros book, and has had no wider uptake, I don't think. Didn't make the cut into MotM, for example, as satyrs did.
I don't think the word cat even appears in the description of shifters -- weretiger ancestors being the closest thing, and only one of two speedy options.
So there's tabaxi and a small subset of ardlings (1 of 16 examples given).
Of these, would your objection disappear if they simply removed the example of "cat" from the list of creatures associated with the climber option?
For most players, there is one cat race -- Tabaxi. Players who want to can add catlike characteristics to two others, where it is completely optional and has no menchanical effect.