It takes lots of guts to take over a team that's actually playing win one game, draw two games and lose three games before winning again. That was the situation Manchester United found themselves and Amorim left his winning Sporting side in Portugal to England to catch a depleting team. That's enough guts for me, yes the team ended up badly but for the benefit of doubts I personally didn't judge him because he didn't start with the team and didn't also buy the players.
Before he accepted the offer he should have first considered all this mentioned. He believed he could turn things around and it turned out his expectations weren't met at the end of the season. The offer came in and he didn't bother doing his analysis properly so he could decide either to accept or decline. Last season is now a thing of the past, the judgement will commence with the performance of the club this season. Amorim was carried away by the Manchester United thinking he could earn credits from the club but anyways its not late to prove a point.