You guys don't pay attention very well do you? First dude walked into him as Sierra's friend tried to stop him and said "Are you fucking serious?", meaning the dude was probably already hounding them. Second lady stood close to the ledge with that chair blocking the way, watched him coming and then got closer and turned her back to stop him.
You can call him a dick for skating into them but it's not like they are just passing by and didn't see him. They actively got in his way to prevent him from skating. It's not like he was just out to tackle people in China.