Suggest you take a look at the video on youtube at the 2 minute mark, then tell us again that it was the GK who nudged Williams and by doing so ended up against the boarding and on the deck.
Just watched the EvertonTV replay of it and the commentator even uses the word nudged because that's absolutely what happened. It was clever from their keeper and he got the better of Williams by doing it. Williams is a competitive player, was playing for the losing side, and doesn't like being outdone so his reaction was quite understandable in my opinion.
I think some are going way over the top about any malice intended by Williams with that particular response. Acting as if he wanted to cause the keeper harm and could have smashed the keepers head in to the advertising boards etc. It was a split second reaction, and was a bit pathetic that's all.
Found his reaction to the goal worse in that he smashed in to that player for no reason, but again, I can understand it because he wants to win and is a physical player and emotions were running high. The way some are going on, it's like they've never been involved in a physical game themselves or ever let emotions get the better of them.
And when our players just whimper to a defeat in games like the Anfield derby, the same fans will be crying about how none of our players care or bother to get stuck in. In sport, part of getting the better of your opponent can be getting them riled and that's exactly what Williams did. It got the crowd fully behind us and we scored soon after, and with a bit more luck, could then have gone ahead if the Sigurdsson freekick had have gone in.