Jealous people seeking demands by making threats. It is like "peacefully" taking the police hostage. They can easily use their paintball guns and batons to clear the path. But they don't.
So much for being intellect and studying in University. If I want to negotiate, I will use my brain. For example, we have been collectively boycotted American products until they rationalise their ambition here. No longer local franchise operators are being pushed to achieve unimaginable targets like opening 1,000 outlets in a year. Then we weeded out greedy software giants from educational institutions by making students and academicians agree to not use non-open source software in campus. After 5 years, now we always got 50% student discount whenever we buy something from them. As a payback, we agree to enforce the piracy law.
Taking cops as hostages is useless.
Cops are paid with your tax money, they bring home shitty amount of money, let alone doing a lot of dangerous stunts that many refused to (like flipping burgers, instead, taking a student loan that they don't have a plan how to pay it back with and hoping to secure a job like pushing papers and get paid big). Simply put: they just got too much shit to take care of. Another whiny able-bodied teens are nothing compared to pregnant young moms being held by armed robbers situation.
The use of pepper spray in the other hand, is a bit too much IMO. It hurts people, but apparently their threatening gesture of shaking the pepper spray can isn't taken seriously.