Queen & Spadina G20 protest, what happened?

I have been watching a lot of footage from the Queen & Spadina G20 protest yesterday and I’m sorry to say this but I don’t understand what gives the Police the right to treat people the way they did. Here is just one of the videos on YouTube which demonstrates what happened over the almost 4 hours that innocent people were pushed around like cattle and forced to stand in the rain without any communication from the police.

I was sure Canada was a “free” country where freedom of speech was respected and encouraged. This was demonstrated when a group of Tamils were allowed to shutdown a major highway into the city nearly two years ago. What was different about this, what looked like peaceful protest, that warranted such drastic action from the Police?

I understand there was violence and property damage at the same location the day before.
That however was caused by a few members of the “anarchist” group whose agenda was not to make their views known but only to cause damage.

Why did the Police hold innocent bystanders captive for hours without giving them a chance to leave if they wanted to? It was quite evident from the many videos posted on YouTube as to who the bad apples were, they were the loud, obnoxious ones throwing swear words at the Police officers. Why not simply go in and target them, let the innocent people go.

It’s not enough that tax payers had to pay over a billion dollars for a three day meeting of the minds which accomplished nothing new. They have to be treated like cattle too?