Because people hold him to a different standard than everyone else.
If he misses a single pass then you know it will be brought up after the game. Yet Rodri, Laporte, Stones and Cancelo all fuck up equally simple passes in infinitely more dangerous situations and it's been forgotten about by full time because they all had great games.
We did not see the worst of Sterling tonight, not by a long stretch. We all know what that looks like and it looks a damn sight worse than an under-hit ten yard pass. But it's that exact sort of hyperbole that encapsulates why the majority of the discourse around his performances is absolute nonsense.