Don't get me wrong. I was at the game and was unbelievably frustrated by what walker did in the build up to the 4th goal and I think his defensive performances this season have been disappointing. If a player makes a crucial error like that then of course supporters are going to have a moan at the time.
But once it's done you have a duty, in my opinion, to get behind the guy and let him know that there's a way back from a spell of poor form.
You don't go on twitter calling him a cunt, or whatever it is people did