Apparently, Warner Brothers stopped producing their most overtly racist and ethnic stereotypical images in cartoons between the 40's and 50's. The more casual stereotyping faded away over time. Yet, they continued to air the early stuff until 1968.
Violence in cartoons comes from slapstick in newspaper comics and silent movies. As the old saying goes, comedy is misery happening to someone else.
Forensic examinations of ancient bones show that humans killed for camping spots, sometimes eating their victims, and enslaving their women. They probably laughed about it at dinner time.
Modern humans would never laugh, nor celebrate, the deaths of others. Oh wait...
Watching Looney Tunes is a way to purge yourself of the worst human tendencies. Anyway, it's better than eating your neighbors.