Education goes with owning a firearm, yet it isn't required to own one (in the USA, at least)

While a single negligent node runner can't cause much damage (unlike with a firearm), if the vast majority of nodes are run by clueless operators, it can cause problems with consensus if, for example, they are persuaded to update to a malicious client (a la. Segwit2x) without understanding the ramifications.

The ability to run a node is open to anyone, but it comes with some level of responsibility.