It does look as though the sidewalk is accessible, at one end, only by stairway. Bicyclists could carry their bikes up those stairs, but they shouldn't have to. The way I load my bike I'd be capable, technically, of doing it. But I wouldn't.
I notice, also, that at least three other vehicles came up on the rider far too fast and far too close. The pickup nearly clipped him with the trailer.
I wonder why the video does not show the moments just before impact?