One of the reasons I don't really follow football is the undercurrent of acceptability of fan (and sometimes player) behaviour that would never be tolerated in other sports and the way the authorities more or less turn a blind eye to it. I fully believe if you let people behave aggressively and gloss over altercations as being 'high spirits' and the likes then you are just sending a message to the fanbase that it's OK to be that way and so on and so forth.
This is what (IMO) leads to this sort of thing happening
https://www.bbc.co.uk/sport/football/51290264
Whatever you think of the way Manchester Utd. is being run this is not the way to protest... he has two young children and having a mob chanting death to their father and attacking their home could have been very distressing to them... hopefully they were't there. Absolutely disgusting behaviour, but I bet no one will be charged let alone sentenced.