Basically what Keane said was right, bad defensive mistakes first from Shaw, was he trying to play heading tennis? Then Maguire he got caught weight on wrong foot, and finally De Gea tries to push a shot away (that he could save with his body) over the angle, when he clearly was not positioned correctly. All mistakes you wouldn't expect, but because they all occurred in an exceptional sequence that led to the loss of a goal, they looked much worse.
Roy just lets his mouth runaway with him, happened before will happen again, not unexpected, highly predictable, its what makes Keane such a 'marmite man'.