How do you love kittens but hate cats?

I am baffled, about 15 years ago I met a guy who said he loved kittens to death but did not like cats, Toms and queens; almost to the point of loathing them. I was wondering how you could love kittens and not cats? Does it change things if it is your kitten? When do you know a cat has gone from kitten to cat? And how would you just shut off all the emotion and/or love you had for the kitten when it is no longer a kitten? Unlike humans cats kind of become cats right under your nose –and quite fast too—. My niece’s cat had kittens about 6 weeks ago and though you can see the development from new born kittens to when their eyes open and they get large enough to start romping around they will get bigger, longer whiskers, legs, and tail. But how would you say “now she is a cat, a queen” and if you loved kitten and not cats stop loving the cat you loved as a kitten now that she is not a kitten anymore? I am baffled as to how you would do that?