Cap'n,
I've got a lot of work experience with chainsaws from my much younger days.
A few observations:
1. If he was running that saw without a chain, then it is pretty much just a noisemaker. We have a local neighborhood that goes all out for Halloween ... they block off some streets and the parents go all out for the kids. Kids come in from all over. One of the parents puts on a Leatherface mask and walks around with his running chainsaw - WITHOUT the chain - to scare the kids. It's all in good fun and he is definitely NOT overly aggressive.
2. From the two photos of antifa chainsaw boy, it sure looks like he has a chain on that saw.
3. In the second photo, antifa chainsaw boy proves that he is a stone-cold idiot ... holding the saw above his head with his left hand wrapped around the blade. For his sake, I certainly hope the motor wasn't running. If it was, that was definitely a Darwinian, "Here ... hold my beer and watch this!" moment.
4. If this was in Texas and he came at a group of women wildly waving a running chainsaw - with a chain on it - I'd drop him with a .45 slug in his chest without thinking twice.