Think I see that stupidity in the scene just previous to Abraham saying this. Abraham goes out to retrieve an RPG from a live walker and rather than use his knife like has been done countless times to kill it, he risks wrestling it and miserably fails but, at least isn't bit. If that isn't Grade A stupidity, I don't know what else would qualify. The fact that he got it by fluke after was just as dumb. Guess writers have to have their bad moments too.