Earlier quoted context omitted.
That attitude is the weapon of suppression. Yes, it's true that life isn't fair. But it's also true that people have agency and can make material improvements to their own quality of life through smart decisions and dedication. Of course most of us won't start the next Google, but that doesn't mean dreams and hope are bad in general.
We have no evidence that people have meanginful agency, or even agency at all. It is an assumption that to start with requires that the universe is not largely or entirely deterministic beyond what we can measure, but even in the case of some "hidden variable" that provides agency (try to even define it in a way that doesn't make it either deterministic, random, or a combination that implies no actual control) we hav…
But, as you said, we still all make decisions every day, and those decisions do affect our lives. So by acting as if we have agency, we can still have a positive impact, both on ourselves and others.