No sweatpants

I’ve been working at Lowe’s since last winter(January to be exact) and I have never been told no sweatpants. Obviously it’s winter so I was wearing sweatpants when my ASM last Sunday said I couldn’t wear them. He’s hounded me before about stuff so I wasn’t shocked. But I was told no sweatpants in January and it’s been cold since October and I’ve worn sweatpants since. Is there a policy against no sweatpants? I don’t remember reading anything about it or being told at all up until January. He told me jeans and khaki pants only and obviously shorts. I don’t own any pairs so that’s why I’m asking before I go and buy some. Would like to hear some feedback