Ignoring all the perks of lowering dex

1) lowers item carry limit a bit
2) lowers skills that rely on dex
3) dodge characters usually have minimal carry weight + str stat coverage to prevent weapon drop, which means you'll rarely nerf strength to effect carry weight where dodge will be significantly impacted
4) 25 dex max weight dodges better than 15 dex max weight and probably better than 3 dex no weight. So nuking dex will always help, where as nuking strength might do nothing at all to dodge.

I would laugh when anyone used a pure -str thing on my bards.
Though really, both strength and dex are very easy to cover to +15 with relative ease, so unless you're fighting assassins or dagger specs for way too long, most vets are not worried about stat loss.