There is no reason to mix and match the concept of an organized fan club who go into the stadium and cheer for 90 minutes for their club with the concept of Ultras.
Inter has a lot of fun clubs in Italy and out of Italy who are organized and go in the stadium with the only purpose to cheer for their team. They don't feel entitled to get free tickets or extra favors because they are paying for a membership fee or because they are going in the stadium more often than the general fan.
Ultras on the other and is a culture of violence. It has nothing to do with sportsmanship , nothing to do with the love for the club and nothing to do with the atmosphere in the match. Ultras culture needs to be punished by law and the leaders who incite violent behavior need to be identified and arrested as simple as that.
I have been part of both worlds ( ultras and just normal fun clubs) and i can tell you that there is a major difference between them. Both are fans of the club but ultrases do not love it more than the others , nor sacrifice more they just like the culture of violence. As a fun club you gather , you discuss about the match , the players , the tactics and together go watch the match.
As an ultras , you gather , you do discuss about the team but mostly you focus on the opposition fans , you plan what to do to SHOW them , how to steal their banners , how to throw blasters on their side of the stadium and how to make noise. As an ultras you want to be noticed , you want the medias to speak about you and you want to be PART of the match. As a club fan , you don't want to be a protagonist , you go there to serve the club ( cheer to motivate) not for the club to serve you.