They were buffed for being short, and thus shitty. They were buffed because it was a better idea to bring the lesser used 2h weapons up to par with the greatswords, than simply nerfing greatswords to the level of less used, underpowered weapons. Realistically it makes sense for longer, heavier weapons to do more damage, but from a balance perspective where length is the king stat(length was/is king irl as well), it only means that with the old stats, those weapons were in a shitty position.