Aachen is in the German far west. That means, by extension, that they have a bit of a cowboy philosophy.
Going to the grocery store is a big deal in Germany. Most everybody makes it an outing. The women put on lipstick and brush their hair while the men do their damndest to avoid going to begin with - but if they're going, they're going with a vengeance.
Enter the shopping cart/trolley dilemma. There is a certain protocol in obtaining, handling and getting rid of your shopping cart in Germany. While the Germans aren't nearly as polite in waiting in queue as are the Brits, they do tend to wait their turn. But it's anybody's guess as to why the elderly gentleman attempted to wrest the trolley from the threesome, except that he was NOT going to wait any longer than absolutely necessary for one. And based on the story, it would appear that the threesome felt power just by being a threesome. In any event, the elderly gentleman felt that protocol had been violated. And as anybody who has spent more than 10 minutes in Germany knows, any violation of protocol can result in presentation and use, if necessary, of a prescribed weapon.
As lethal weapons are generally not available to the common citizen, other weaponry includes use of a raised voice. Or as we have seen in this case, a salami.
Don't laugh! Salamis are hard! With a pretty tough skin on the outside! And they're usually pretty thick, which goes a long way when you're trying to feed a lot of people.
I'm kinda wonderin' if they have a sunset in Aachen. You know, like the kind John Wayne would ride toward at the end of the Lebensmittel fight....
Damn, I had fun with that.