Recruit Lawrence didn't have it so bad

After watching this movie many times over the years, it seems to me that Lawrence's descent into madness doesn't make much sense. Hartman was tough on him, but it never got crazy. The beating from his platoon was harsh, but he became a good recruit and he was even praised by Hartman.

Had he kept messing up or was told that he would not graduate like the others, his actions would have made more sense.