The gnus aren't the problem. There are millions of gnus out there that are handled just fine. People have been handling gnus for ages without problem.
It's the behavior of the gnu owners that are the problem, particularly the mental health of a handful of gnu owners.
Most people who own gnus are responsible. Nearly all gnu owners can handle it. It is only the tiniest sliver of the gnu-owning population that have problems.
And those problems are normally mental health concerns.
It may be from people who want to try suicide by gnu, or people who lash out at others running and use their gnu to rampage through the market, it is the gnu owners and their mental health that are the problem.