I remember from the late 1970's thru the mid- 1980's when many of the networks began to drop cartoons from the Saturday morning lineups. There was a lot of blame put on violence in the programming such as Looney Toons, some of the superhero type shows, as well as 'toons which were spun- off from real life TV shows.
Actually, violence had been gutted from adventure (superhero, etc.) by the end of 1969. For example, Filmation's superhero series produced between 1966-69 contained a good dose of violence associated with characters of that kind. Like a night & day change, by the end of the decade, it was gone (see: their 1977
Batman series).
Guns, fists, kicks and death (by any means) vanished from nearly 100% of network series of the next two decades, save for rare exceptions, such as the occasional struggle & Phaser shot on the animated
Star Trek, & gorillas threatening with rifles on
Return to the Planet of the Apes (both NBC).
On the syndicated front, things were a bit different; imports--even when edited--retained a level of violence (seen or implied) no network production would dare touch, hence the reason the awful
Super Friends (ABC) was a collection of glorified finger wagging, rather than anything kids would have expected from a superhero group.
The syndicated Battle of the Planets felt like a true superhero program more than the nationally established DC characters from the
Super Friends.
Even the great
Jonny Quest was edited when rerun on networks in the 70s /80s, along with removing allegedly culturally insensitive content.