I don't think it is amazing at all.
It is like the Trump effect. Everything was fake news, never his fault, everyone else was to blame
In our case it is Mourinho. Some people set in their views. Everything good is down to him , every bad is the players fault. Apparently every player we have should have the best XG rate in the world (which Son basically did have for part of season, which is why our results were outperforming our performances) , and our defence the best XGA in the world.
I have even seen it explained that it is right to take 1-0 lead and then just try and defend for the rest of game, because winning 2-0 is a mistake, because it shows that by getting a second goal you didn't trust your defence to keep a clean sheet. Lunatics have taken over the asylum.