The wiki for short shorts indicates that it's exclusively for the type of shorts also known as "booty shorts" or "hotpants", whereas the naem alone would indicate it's for any type of shorts that's short. Shorts that have a short inseam but aren't tight (for example: post #3553597, post #3700754, post #6941544) are inconsistent as to whether they're tagged as short shorts. Just look at rosa_(pokemon) yellow_shorts short_shorts versus rosa_(pokemon) yellow_shorts -short_shorts - that's not far from an even split.
I would suggest making the tag based exclusively on length, with no regard for tightness or material. I'm not sure whether it would be better to make booty shorts or hotpants its own tag, or just ignore them and let denim shorts and bike shorts pick up the slack.
I'd also suggest making a new tag, medium shorts, for shorts that are legged lower body wear longer than short shorts but shorter than capri pants, like medium skirt.