I do agree with it, but... Amazon
is regulated. They're already not allowed to murder or enslave people - and they still come as close to wage slavery as they legally can in their warehouses. The law doesn't require them to care about the homeless, and the market doesn't seem to care about them caring about the homeless, so Amazon doesn't care about the homeless.
Their culture is legendary for its relentless focus on cutting costs and driving employees hard for the sake of the bottom line, at all levels. I cannot see them spending a dime on fighting homelessness, even as a PR move, unless they expected to make a dollar back, that's just the way they operate.