In general there are many different grocery stores, even Walmart the massive company it is only represents something like 10% of grocery sales in the US.

Amazon represents something like 40% of all online sales. Typically having a large plurality in a market raises the likelihood of actions against you.

>It seems to be a pretty close analog yet nobody bats an eye at the practice.

Or, more likely, tech people pay attention to Amazon and not the myriad of suits occuring in the retail and grocery world.