Dude the word assault rifle barely means anything. Mp5s are fully automatic weapons. I would say they're quite capable of assault. And they're rifled firearms, so they're rifles.

It’s just a classification.

Adding to that, these rifles or machine pistols weren't used to protect against hooligans, but against the risk of islamic terorism.

Hooligans can be bad, but they are not gunshot-bad. Riot gear typically suffices. And most hooligan action is anyways happening outside the stadiums nowadays.

You have a point, but do remember that a properly kitted MP5 can give an untrained eye the impression of an assault rifle.

Generally, I assume the public thinks that anything physically bigger than a pistol and smaller than a rifle is an "assault rifle".

PSA: Assault rifle isn’t a real thing, it’s a political term that depends on the cosmetic qualities of the firearm that anyone with some basic tools could change in 5-10 minutes, like the style of the hand grip. It has nothing to do with caliber or lethality of the weapon.

If you wanted, you could own an MP5 that would be categorized as an assault rifle, to do so you would need to make it LESS lethal, by converting it from a fully automatic weapon into a semi-automatic, and would need to put a longer barrel on it. Such versions are sold in the US.

Your heart is in the right place, but you are incorrect. The made up political term in the US is "assault weapon", created when the "Assault Weapons Ban of 1994" was enacted into law.

"Assault Rifle" is very much an actual term for an actual classification of military firearm, and is a literal translation of the German term to English from the original assault rifle, the Sturmgewehr 44 created by the Germans during WW2. Moreover, the reason an MP5 is called an MP5, is that the MP stands for Maschinenpistole which literally translates to "machine pistol", and is the next closest type of weapon in German parlance to an assault rifle. In fact, the StG 44 derived from the MP44, which fired a smaller cartridge.

Mechanically, both assault rifles and machine pistols operate similarly, the primary difference is the cartridge. Assault rifles fire intermediate rifle cartridges (smaller than a battle rifle cartridge) [e.g. 5.56 NATO (.223 Remington)], and machine pistols fire pistol cartridges [e.g. 9MM NATO]. Machine pistols in the US are classified as sub-machine guns. The history of that is equally interesting, but irrelevant to this sub-thread.

There are no civilian owned Assault Rifles manufactured after 1986 in the US, except when held by a Class 3 FFL (federally licenses firearms dealer), or purchased by a police department or specially licenses corporate security organizations (think PMCs). They are considered to be exclusively military weapons that do not pass the "sporting purpose" test enacted in the Firearm Owner's Protection Act of 1986 (ironically named, since it didn't do anything of the sort). This is especially ironic because the entire reason shortened barrel shotguns being illegal in the National Firearms Act of 1934 was upheld in the US Supreme Court (Miller v United States) is due to it not having a military purpose, the purpose of the 2nd Amendment being that US citizens have an innate right to possess, train with, and utilize military equivalent arms. So taken together, in the US a firearm must have a "sporting purpose" and also be military equivalent in order to be legal... luckily that contradiction does not completely eliminate most firearms.

Yeah, I'm not a gun guy. Looking up MP5, I see that it looks like what they were carrying. To me that's not any kind of "pistol", but I don't know the correct terms.

It's a SMG. Sub machine gun.

In German it is called Maschinenpistole, hence MP.

I did see the German police with assault rifles during a protest when I lived in Frankfurt. They may have just been rubber bullets or not loaded etc. I never stopped to ask because it was a little scary coming from a country where you just don't see guns.

That being said, I have no idea about how they police football games, so you may well be right!