Appears to be dashcam idiot's fault. Both deserve to have their license taken away for some time, dashcam idiot should have a bus pass for a minimum of 2 years, the other needs some more driver education, a lot more! Both are in the territory of reckless driving for their actions after the collision.
Here is a thought none have brought up yet, if they both have the same insurance company, often in a case like this, they call it a "Push" and assign no fault since they are paying both sides anyways. Mr. dashcam does not have to show his video footage. "Don't ask, Don't tell". If a driver was cited at the scene, then they would assign fault and raise Mr. dashcam idiots premiums due to a point on his/her DMV record.