// He was wearing running shoes, track suit bottoms and a T-Shirt. How is that not looking like a jogger? //
Because nobody actually jogs in joggers.
Joggers are worn for, for instance ...
... watching telly on your own
... curling up on sofa, drinking wine with a gal pal
... reading the Sunday papers
... shopping in Tesco (#bait)
... pushing a buggy if the age gap between you and your child is quite small
... hanging around outside shopping centres
If you actually jogged in joggers, everyone would think you were a shoplifter running away.