This is the report the article cites

https://www.accountable.us/wp-content/uploads/2022/04/2022-0...

The report is not very well reasoned in my opinion. It appears mostly just to be against inflation in general since the definition of inflation is the price that ordinary consumers pay for goods at ordinary stores. If the article said "general inflation is 8% but wal-mart raised its prices 15% in areas with no competition" I would get that and be mad - but the report doesn't even say the price increase at these stores. It just cites the total increase in profits (without specifying if this is due to more total revenue, high profit margin, or lower costs)

The only exception I can see in the entire report is that Costco rose prices 5% - which actually seems less than inflation.