In the same way in which thousands of fans have seen gangs kicking and punching lumps out of each other, most notably during the seventies and eighties.
Sorry, I missed the 'irony'.
And yes I've been watching football for 40 years, travelled all over the country - of course I've 'experienced' hooliganism.
Whenever I read about middle-aged men (and older) discussing with great relish the joys of hooliganism, past and present, it makes me cringe.
Hooliganism is a pastime reserved for small-minded, moronic loners with deep inferiority complices who cling desperately to the plaudits of...other...