It's both funny and cringey. Is it unprofessional and a dick thing to do? Yes. It's also hilariously absurd.
Wearing shorts is "unprofessional". Why? I don't know. I sling code, pants aren't helping or hindering with that. I grabbed shorts this morning, let's not make it complicated.
Today we found out, it would have indeed been hilarious. (But yes, a dick move)