Or take their picture and run to the guys who carry guns.Wrong
Inciting a crowd to commit violence against a person - You as a citizen can arrest that person - using as much force and only as much as is required.
Threatening to harm a person - you believe that this person is going to harm you or kill you - You as a citizen can arrest that person or defend yourself- using as much force and only as much as required
Yelling Fire in a crowded Theater - Causing a high probability that others will be harmed - You as a citizen can arrest that person - using as much force and only as much as required.
Oddly enough, in Canada, the ones instigating violence against the Police has been shown that they are Police themselves. You are suggesting you would go over and arrest them using force if they (plural) did not obey your commands. I hope somebody films the way you died.