So, this is not an argument in favour of what the police did last Sunday (it was wrong, and I hope the police and their bosses are held accountable for that), but this exercise is too interesting to not share it here:

This happened six years ago. The same separatist party was in power. This is the regional police, and this is downtown Barcelona:

Quoting you verbatim, except for what’s in bold:

“The fact that for whatever reason, the Catalan Regional Police were committing violence against Catalan citizens in an attempt to stop them from assembling peacefully, is an affront to democracy, I don’t care what they were demonstrating for.”

I’m sure you will disapprove of this, too. And rightly so. My goal is just to show the true colours of these “profoundly democratic” and “for-the-people” Catalan officials who are leading “the people” into the future via “pacific and non-violent means”…