These comments are silly.
First, regarding last year's world championships: Of course, lots of people can run 1:02:31 for a half-marathon. Lots of people can also run 14:17 for a 5K. But very few could run those splits under those conditions in Daegu. And if there's anyone in the world who could actually run 2:05:02 under those conditions, you better believe that he'd be good enough to medal in the Olympic marathon.
Second, regarding Makau: If you haven't read anything to suggest that Makau was injured when he dropped out in London, then you simply haven't been paying attention. And Makau has not won all but one of the marathons he's started. In fact, he's only won one of the last three.
Third, regarding G. Mutai: Of course, I did not "miss" his 2:03:02 last year in Boston. I simply recognize that it wasn't a personal record under any generally accepted standard. G. Mutai's PR for the marathon is only about nine seconds faster than Kirui's, and on the same course.
Finally, it's perfectly O.K. to have your own opinions. But don't suppose that you know more about these matters than someone like Ibrahim Hussein does.