People express themselves politically through voting. These people in particular had every form of expression available to them. They discussed whatever they wanted, and I can provide you with links where you can see those discussions
I think this riot is best understood as being actively organized by the current ruling party.
I think there is a clear free speech issue in the current politics though -- systematically devaluing the potential for productive political talk is a form of free speech restriction -- it's a ddos attack against rational discourse - which has the effect of reducing the value of political discourse in general.