My point is to help you not forget your compassion. All this talk about agency is nothing if you don’t have the luck to go along with it. So if you see someone who’s homeless, don’t talk to them about their agency. Just help them.
Trivializing homelessness like this doesn't help, and I strongly disagree that "agency is nothing" to unhoused people. There are many free resources available, but the organizations providing them often don't have the capacity to efficiently allocate them to those in need, due to difficulties with reach, etc.
Escaping poverty is a function of others' generosity (luck) but also agency; you can't do it without some amount of self-belief and proactivity and exposing yourself to opportunities for aid. But it's very difficult and a lot of people give up.