Sure, if it's one or two people then yeah it can still be labeled peaceful. But when it's 10 - 20 or more rioting and inciting fights / vandalizing / doing illegal stuff, then it isn't exactly peaceful, now is it?
10 people out of 1 million is literally 0.0001% of the entire protest. Even if its a more realistic number, say 10,000 people at the protest, 10 rioters still makes 0.01% of the entire population
if like 30% of the protest was violent then that'd be closer to a violent protest, but that's never happened before.