It appears that the police, in an effort to contain both protesters and thugs, managed to upset everyone, including the legit protesters.
This country has a long tradition of hot blooded and colourful marching protests and that is never going to change. Heck, I've even been on a few myself, but yesterday was different. With the ultra Kirchnerites now in opposition and La Campora weakened by the very fact of their opposition status, one suspects that what power base they still have left, may be responsible for the 'hired hands' we all saw tearing up the streets yesterday.
I believe the violence was premeditated and I'm not just saying that because Macri said it. It had all the hallmarks of organised football violence and it wouldn't surprise me to find that many of those detained were indeed known for throwing themselves around on the terraces of Boca or River.