Not to speak for Dave, but this doesn't have anything to do with AEW. I enjoy them, but there are better and safer ways of doing this. And believe me. If that mess was happening in the E I'd make the same complaint.
The reason AEW gets the backlash is due to their exposure to the mainstream. Smaller promotions aren't on TV on a weekly basis and can do large scale events. A few years ago, the E had that promo telling folks to not do that crap because they realized how kids and others were trying to pick up and getting themselves killed. Private company or not, AEW has a responsibility in this.
Let me also say that it's not just the Swerve/Hangman match. What happens if a kid tries to mimic Moxley and throw a plastic bag on another kid's head and something tragic happens?
In a world with YouTube and the internet, any child or any idiot can pick this up.