Like fodder was able to damage WB, but he definitely didn't have 400+ slash wounds and bullet holes on his body. So how much damage did most of the fodder actually do? Probably not that much. Additionally, the only times we actually see fodder damaging WB on panel are 1) when squard sneak attacks him and 2) right after akainu damaged him. Both of those circumstances are a little extenuating tho.