Paragliding requires ascending currents to maintain or gain altitude, IOW you're always going downwards relative to the surrounding air mass. Birds don't (although they obviously do know how to use it for the cheap).

I think maybe the GP is more amazed about the (self-) generated lift and assorted scale. Seems like humans have a thing for hurling self-propelled heavy metal boxes at ridiculous speeds, whether on ground, in the air, or in a vacuum.