What cartoons (or kids shows) are you talking about? I watched cartoons in the 60s-70s and saw no such message...
Compassion for animals is not anti-human, it is a good trait for humans to be compassionate to animals.
Just about all the shows when I was younger, if they had an environmental message at all basically sent the message that humans were nasty creatures that weren't in harmony with nature and too many people meant pollution and animal suffering.
I've dedicated a good part of my life to helping animals in various ways so of course I agree that we should care about animals and being good stewards of the environment, but the problem is Muman is that communists have put nature ABOVE human beings and they think that the life of a guppy in a pond is worth more than a human life.
Just look at PETA and their disgusting advertisements showing chickens compared to Holocaust victims. Those liberals are so dense that they literally think that the life of a chicken means the same thing as the life of a human being. In their addled minds the moral equivalent of a holocaust is going on every day at slaughterhouses. They see humans as being the evil creatures that are causing this for animals.
Even in SOME of the older programming there might have been a little bit of a message that was turning that way. Look at Bambi for example. "Man" is seen as the ultimate enemy in that movie, hunting down Bambi's mom and setting a forest fire. That kind of theme pretty much became dominant over most of the programming when I was younger.
It culiminated in outright libtard shows like "Captain Planet" that came out in 1990. That was playing when my sister was younger. It featured a group of multiethnic kids from around the world coming together to fulfill the libtard dream and every episode had to do with evil human beings harming the environment. There were also outright witchcraft promoting movies like Fern Gully that basically said if you cut down a tree you're harming the tree spirits and you're a bad evil person.