If you’re too inflexible about the way that language is used informally, you might drive yourself crazy for no good reason, like when people got all bent out of shape during that brief period in the 90s when ‘bad’ meant ‘good.’
So sportswear isn’t limited to things to wear while participating in sports? That’s right; big deal. Sport isn’t just what happens between the lines on the field. That feeling of unshakable confidence that comes with achievement and looking good is a way of life.