Is it normal millions of kittens are put down due to over population fear?

What gives humans the right to do that? And if humans are so concerned with overpopulation, why don't they put down their own, humans are 8 billions, no other mammals except filthy greedy humans have a population over 1 billion (except cattle but thats still just 1.5 billion almost 8 times lower). What gives humans the right to do these:

Millions of kittens are put down due to overpopulation - YouTube (link will be in my comment)

I wrote a previous post on similar evil act on our fellow beings by humans, the issue of trophy hunting:

https://www.isitnormal.com/post/is it normal we-should-stop-animal-trophy-hunting--265701

The world would be a much better place without filthy greedy humans breeding and destroying it and killing countless animals who never harmed them ever, put your useless unwanted kids instead of harming other animals who can't speak their voice on their own rights!