To expand, It doesn't matter if your protest is valid or not (e.g. the people protesting in the OP vs BLM riots), blocking the streets only fucks over other people who did nothing wrong and may even agree with your protest. If you want to block a road that only the government (or whoever else you're protesting against) uses to prevent them from doing whatever they might be doing that's one thing, but why fuck over your fellow citizens by blocking the regular roads they use?
That isn't a counterargument.
To expand, It doesn't matter if your protest is valid or not (e.g. the people protesting in the OP vs BLM riots), blocking the streets only fucks over other people who did nothing wrong and may even agree with your protest. If you want to block a road that only the government (or whoever else you're protesting against) uses to prevent them from doing whatever they might be doing that's one thing, but why fuck over your fellow citizens by blocking the regular roads they use?