Is it cruel to make your pet wear clothes?

Personally only if the weather is too hot, the dog already has thick fur and the owner decides to dress it up with matching shoes, I call it torture. I saw this girl bring her Shih Tzu at my son's school and just looking at it made me uncomfortable. I don't have the heart to see my own dog suffer heatstroke. It was a school recognition day and the hot sun is already out at ten in the morning and the girl looks like she attended a fashion event which her dog got dragged into. I think a pet owner's priority should be the needs and comfort of the dog.