I think it’s a very shallow and naive assumption of yours. People are different. There are people who care about others, the world, the environment, etc, more than you or anyone else who have children. Also, there’s people who have children and only care about themselves.
It’s very dangerous to label people based on a single fact in their entire nature and life. That’s what fascists/nazists did in the past and we all know where it ended.
Get rid of your own limited view of the world.
PS: I do have children, in case you’re wondering.