This person sounds incredibly negative and delusional. We're not animals that put people into a job in there 20s and say your career is over in 15 years.
If your worldview is that people are animals, then yeah, you know. Work on yourself.
You are correct, we are not animals. I do not view us as animals, but it is not my view that matters. The view that matters is that of the corporations who do the hiring, and for the most part they view us as expendable resources (I mean, come on, it's literally in the term "Human Resources") to be acquired and used until all possible value has been extracted from us, at which point we are discarded.
This, I feel, is ultimately where ageism comes from. 40 is not just some number they pulled out of their collective asses, it's the approximately-average age where the cohort that joined the DP/IT workforce in the 80s and 90s is burned out and used up.
I think this is a human condition. I passed by a department store recently and all I heard were the cashiers complaining about their job. It's what people do, they literally cannot stop complaining about their apparent slavery.
The older I get the more stubborn I've become in my beliefs.
If your worldview is that people are animals, then yeah, you know. Work on yourself.