Like many phrases of the moment, "stay in your lane" gets overused, but there is little point in keyboard warriors deciding to give advice to activists on the street. It is silly to judge their actions based on what you know are incomplete and biased-towards-authorities news reports, especially if you somehow imagine yourself to be "on their side," and a big error is judging the actions of normal people more harshly than those of the people we pay, supposedly, to keep the peace. One doesn't have to condone violence to understand that sometimes things get out of hand when there are large groups of people in intense situations, including sports victory celebrations, and the "mob" is not collectively responsible for all actions of all individuals. One thrown water bottle should not lead to tear gas and batons.
It's clear by now that while there unsurprisingly hasn't been some amount of opportunistic theft (looting is loaded word, also, too), the people escalating violent situations are the people tasked with preventing violence. Calls for "nonviolent protest" place the responsibility on the people who are almost entirely not responsible for any violence. Direct it at the people in power.