I thought the Hull defender blocked off Cahill's run by closing down the available space and the only options available to Cahill were to run straight into the defender or go down.
Thought the ref actually got that call right.
The decision will have also been influenced by the fact he was lenient towards Myler who was already on a booking and then barged into the back of an attacking player and then threw a tantrum over it. Having been lenient with Myler he again gave the benefit of the doubt to Cahill.
The booking for Costa was an absolute travesty. A clear foul on Costa where the Hull player either caught him on the shin or pretended he was going to catch him on the shin and just pulled out.
The booking for Willian was also wrong IMO. Willian had beaten the defender, the defender just planted his foot to trip him, Willian had nowhere to go so went over rather than running into him and risking injury for both players.
I know that during the match there was a huge whine from West Ham about the pen Sunderland got. But IMO there was a clear shove in the back from the West Ham defender which is a foul. I don't think it was enough to push him over, but if you give an attacker a shove in the back in the penalty area then you're asking for a pen to be given. The simple option for defenders is to stop shoving players in the back, but that's too much like hard work for defenders, isn't it?