I do believe it depends on the animal and the weather as well. I've heard people say their dog really loves wearing a sweater, and if that's the case I guess go for it. There are of course legit reasons to put them in a sweater sometimes, I've read that if it's around 40 degrees or below it's best to have a chihuahua in a sweater when you're taking them outside. I do this for my dog, she has very little fur on her tummy for example, I'm sure it'd be quite chilly for her. However, I know she otherwise can't stand being in clothes, if I put a sweater on her in the house she tries to dig down into blankets frantically, which doesn't make much sense to me. She even shakes her head around if she has to wear a collar. Since I have a fenced in yard, she mostly goes outside there, so I barely ever make her wear anything since I know she hates it so much. So that being said, if your dog hates it and you're dressing them up constantly, I think it is a bit cruel.