basically, when Schwazer tested positive the second time, he had really bad words against him and when it came out that it was a plot against him, he said he didn't trust the investigation of the police corpse and refused to change his opinion on the facts and about Schwazer himself
he was really rude and didn't show any empaty
so, some Italians (me included) don't have a positive consideration of him outside the athletics' stadiums
moreover, some people don't like his clownesque attitude on the track (from the half beard to many other little things)
personally, I don't care about that, but I will never forgive him for his behaviour in the Schwazer's case