Awesome flying. Only a very few people possess the skill/guts to fly like that.
Also, for the people on the Bridge...they got to know that there might be a chance they are going to get hurt. It’s just like the people who stand right on the road at Rally races. It’s not the pilot/drivers fault if someone gets hurt. If you want to stay safe, stay off the bridge/road!
Now if this was an act of random flying under a bridge, I would call that irresponsible, but if this was a closed off event, then the people on the bridge know what they are getting into. If they get hurt it’s no ones fault but their own.