Hi Mogomotsi. The ultra meo-fascist fans would be the ones particularly in Rome supporting Lazio. Irrudicibile or something like that. As for the Milan ultras I think their origins come from the political left. As far as rascism I can say as a Hawaiian person with brown skin, I was treated with kindness and respect from the ultras. The hardest part is being lucky to get a ticket for that area. Even if you do, there is absolute no gurantee you will be able to sit there. That is why I said come early. Be approachable to these guys and most importantly participate.
Another good site to know lyrics and to hear the melodies of Milan Ultras is at
www.tifonet.it
Like Gio said it helps a lot to participate. That way you dont feel alienated or like a dumb@ss.