Because cats have self-respect, they wont become a carpet for you to wipe your shoes on to satisfy your craving for affection that you're unable to get through your affiliations with other people. That's why most people prefer dogs, they crave love and dogs love you unconditionally.
It depends on the people, some people are not cat-people because they don't understand them.
I have a special bond with cats, for one thing I'm not a loud person, and cats appreciate me for that reason: my energy is calming and welcoming to them. So cats approach me easily and rub themselves against me and want to take naps on me. I instinctively have the body language to communicate my moods with them, so they'll know if they can hang out with me or not. I'm sort of a cat-whisperer.
I can't stand dogs (small ones). They're loud, they're either super jumpy/hyper or super bored (they have no middle ground), they smell, they lick their butt or eat poop (for some cute reason I'm sure dog-lovers will find) then want to lick your face, some hump anything that moves, they play tough and bark at cats or other smaller animals but pee and **** out of fear on your carpet and bark every time someone's knocks on the door, and the list goes on...
But hey, some people's lives are empty (not judging), like old people and they need love and something to make their lives more exciting so they get dogs... ok I just realized I'm ranting about dogs. It's just that it needs to come out, I recently just moved from my room-mate's house and they have that neurotic dog that drove me insane!
ps: Cats rule