First of all, you have no ultras at all. You only have hooligans (which is quite a different thing). Secondly, the article got some of the things wrong but I doubt it's bullshit. Bayern's ultras which are called Schickeria (those are the guys that are usually in the South stand during matches) are left-wing. But there is also a hooligan group (or groups, probably neo nazis too) and it's clear that those will look for a fight with Chelsea's hooligans, that's why those guys from London are coming to Munich in the first place (they are not coming because of eating wurst and drinking beer). So they will somehow contact eachother and they will have a fight, nothing unusual for an european football match, especially involving an english team (just like happened in Barcelona when you were playing there).