I always thought of this slingshot guy as the kind of guy who has fun with stuff that only men seem to have fun with. Quite similar to this fella.
The accusations are obvious B.,S. and more importantly, the very notion that asswipe/errorist activity should keep us from doing things that are otherwise fine is 180° wrong.
Just think about it; the guy in the 2nd video did tests with medieval iron helmets (or rather reproductions thereof made of a most likely better alloy). This B.S. storm could have hit him as well if the stabbed policeman had worn some kind of helmet! Ridiculous.
No power to errorists!