Cleanliness & Safety:
Do you want to get goo all over your fur? Is the mud hard to comb out? Do you really HATE taking baths, and the hours trying to get your fur back the way you like? Clothes cover up to protect. Do you work in a hospital? Are you afraid of strangers coughing all over you? Wear PPE. Fireman? You better have the gear.
Status:
Do you like it? It cost a fortune, but you really do have to set yourself apart from the commoners. I heard the deer people don't even WEAR clothes. Poor, pathetic losers. Do you think a deerskin vest would look good? Fur is murder, but it's SO trendy!
Identity:
Those French cats wear short skirts and berets. You can always tell the African tigers from the Indian ones by the sarongs. It's hound, not dog, any proper British hound wears a vest and carries a pocket watch. What, are we German DOGS to be running around in leather like some kind of werewolf?
Dying your fur is complicated and messy, so if you want to show your colors, or team spirit, and still be able to go to work in Monday, it's easier to put a shirt or a robe on.
Religion & Belief:
The prophet said to wear robes, and whatever the prophet says, goes. Civilized people wear clothes, and just because your ancestors didn't, does that make it right?
Setting yourself apart from the Beasts:
Dogs are mangey beasts with no clothes. Just because there's a resemblance, doesn't make me a DOG. Humans wear clothes, monkeys don't. Wearing clothes sets you apart from the beasts.
Uniforms:
A police officer is recognizable because of how he dresses. A preacher wears vestments. A doctor without a coat gets no respect.
Covering sexual signals:
I CAN'T STAND the males staring at my eight nipples all day! You'd swear they never saw a female before. The boss runs around waving THAT THING in everyone's face, and we're not supposed to complain? He rubs up on my ass, that perv, and there's nothing between me and him. THAT'S IT! I'm buying a dress.
Accentuating Sexual Signals:
Fur can cover up one's natural shape, so a tight-fitting body suit accentuates your muscular thighs and is slimming around the waist. Perhaps some mystery around genitalia is alluring. Or maybe puffy fur is sexy, and a faux fur coat makes you look REALLY hot. Human clothes could be a fetish, or a female wearing the skin of a prey animal might excite some guys.