I am not a cat person but most of the time I meet my friend's cats, they like to brush against my legs or stare at me curiously

That's cute.
They want snacks.

If they like you. Most of the time they do want something. Usually it's to be petted. Though if your "their" human it could be food, water or treat as well. Or even just let outside. They do claim certain people as their human.

If their owners have treated them well from kittenhood, yes.

My uncle isn’t a cat person either and yet cats love him

When they want something 😌

I can't say for the staring but cats like to rub against things and people because they have scent glands right behind the neck, and they use these to "mark" people.

Yes.. The rubbing against you is to establish ownership and gazing at your face is to work out which piece to eat first if you suddenly die.

jbird ha ha ha with a name like yours i am not really surprised at your dislike for our feline friends mine does not she is not keen on strangers

Unpredictable psychos