They're suggesting the soldiers, once they die, should burn in hell (which obvs doesn't exist). They're not saying die now, which is the difference. As police I would still ask them to remove the placard though.
If he said it now, yes, as he's in the public eye and he spreading irrational thought and dangerous hatred. It was 4 years ago though so he at least (how much the club intervened we don't know) needed to apologise, which he has, and there is a chance he has learned in the past 4 years not to...