No one has given more disposable income to poor people than Wal-Mart and Amazon. It just hasn't come in the form of wages.
In the US, Amazon Prime has something like 80% penetration into households making >= $100k/year. This move into Whole Foods reaffirms this focus on high-income households, where convenience is often as large a factor as costs.
My hunch is that Amazon has been a massive positive in aggregate, but poor households have been negatively impacted by Amazon, taking into account loss of jobs, lowering of wages, and some positive lower costs for goods.
Households where money is tight are sharing prime memberships among them and using that to undercut the cost of buying consumer goods locally. You can go into your local $typeofstore and get ripped off for a set of $releventproduct or you could buy something that came out of the same overseas factory with a different brand label on it and wait 50hr for a third of the price.
Definitely, to the extent that Amazon puts pressure on everyone selling commodity goods.
To your second point, it's not obvious to me that Amazon has cost jobs at the lowest rungs.
1/ Poor people actually shop at amazon in a significant way 2/ The massive job and wage losses Amazon causes in the poor community are insignificant compared to the "wage gains" #1 would imply.
I suspect both assumptions are false. This sounds like a comment from someone in a bubble like SF where lots of people have the disposable income to buy everything online. People in the rest of the country live very differently.