It may certainly be challenging for other fans to keep extremist hooligans away even if they wanted to, fair enough, but at least they shouldn't adopt contentious symbolism themselves as has too often been the case.
For example here we can see a group of presumably genuine hockey fans that certainly do not appear especially threatening. Yet even they are - whether malicious or not - predominantly waving the Hungarian war flag (
hadizászló) from 1939-45 when the country was allied with Nazi Germany and attempted to annex partially ethnic Hungarian territories of neighboring countries by force. To go with it also somewhat controversial flags of the Hungarian minorities in Romania and Slovakia. These were prominently displayed at this year's tournament as well even without the hooligans attending.
There was also this creation that combines the flag of Hungary and that of the Hungarian minority in Romania (created in 2004) under the imperial coat of arms that was in use until 1918 and today serves as a revanchist symbol for Greater Hungary.
To me this is just very poor sportsmanship, especially when playing against teams of countries like Romania and Slovenia that once partially were but most definitely do not wish again to be a part of the Greater Hungarian empire. If it was a German team playing against Poland and the fans displayed a flag featuring Germany and Silesia united under the imperial Reichsadler I have to think there would be consequences. And there should be.