I don't see why anyone would have a personal gripe with him. As others have said, it wasn't his fault he was given the massive contract he was and he behaved professionally for the most part.
But I strongly disagree with those who assign a greater value to his contribution than was the case. If you want to look at what a successful winger looks like, then see the levels Hazard, Mahrez, Sane, Sterling, Bernardo, Foden, Mane, Saka etc. managed to reach in the PL.
Young never reached those kind of levels and was in many ways an epitome of the averageness of our squad. I find it sort of bizarre that some look back fondly on him but then I guess that's just the manifestation of the erosion of standards that we suffered.