In the course of my life, I've had the pleasure of watching European Champions League, youth tourneys and everything else in between in multiple countries.
The US is the only country where I've felt like in order to be acceptable supporter, I have to have drained a few pints of beer or shots of whisky beforehand.
The major supporters groups all meet at pubs/bars before they march to the game.
Supporting sober is just not advertised as an option.
I could even frame this as an accessibility problem. You see, I can't drink because I take two different medications whose mixture with alcohol would probably hospitalise me. For related reasons, it might be unsafe for me to even participate in the march. I can't be alone. There are legions of disabled footy fans.
Am I wrong? Do you have suggestions? Feel free to comment.