Heysel was horrendous, no argument about that. However it was a riot by both sets of fans that sadly caused 39 deaths of Juventus fans, caused bythe rioting Liverpool fans mainly.
Maybe bear in mind though that many clubs fans have been involved in riots where nothing so extreme thankfully happened.. Our own fans have been involved in rioting, some of which I personally was at, Newcastle, Villa Park and Old Trafford among them. It happened all to frequently at games in most places during games throughout Britain but as said nothing about as extreme as Heysel but it could have for any clubs fanbase, ours included