I couldn't care less who has dived for Liverpool in the past, or who will dive for them in the future, and none of them are relevant to todays game or the point I made. Multiple wrongs do not make a right.
That today was not a foul, and was blatant cheating. He was touched, but not fouled. He has no right whatsoever to bring the referees attention to it, as there was nowhere near enough contact to knock him over or knock him off his stride. He felt a slight touch and threw himself to the ground. Not a foul, not a penalty. Just, unsurprisingly, a cheating United player.