"It is a fact, that while monopolies are good for the monopolists, it is bad for societies at large."

And you are correct. But something different was being said: Unconstrained capitalism, leads to monopolies (or oligopolies). And that's true too. Read your own words. "monopolies are good for the monopolists". Isn't that another way to say "shareholders' profit"? There you have motive. And in a pond of fish, doesn't the bigger, eat the smaller, becoming even more big in the process? That's the process.