You don't know that. At worst they have been treated in the same way Polish soccer fans are being treated.
What do you mean, "I don't know that."
If there's evidence of their misbehaving, then let's see it.
These days, everyone has access to camera in their mobile phone, and there are professional photographers present who would like to make some money from a good picture.
The so-called monitoring camera film shows nothing conclusive whatsoever. Much of the 'arsenal' of weapons turns out to be ordinary kitchen knives.
The rest of the world takes a different view that rioting gangs armed with knives, axes and throwing stones can be collectively punished in the harshest manner.
If the police had shot dead a few of these thugs I'd laugh about it, so we do have something in common - humour .
Go to a foreign country and commit a violent crime and you lose all rights.
Brilliant, Peter, mate.
And if you don't
do any of the above, do you lose all your rights as well?