That if Amazon acquired it, this would enable it to horizontally integrate and take control of yet another market? This, eventually, woudl lead to lower prices for consumers...
The context of the conversation is one of a horizontal monopoly, in a market that's near saturation, operated by a megacorporation that could afford to ignore profits or losses indefinitely, in the specific industry of robot vaccuums. So maybe the question is "why on earth would someone think supply and demand does apply here?"
I believe he’s asking why the parent poster was suggesting monopolistic consolidation would be good for the consumer, contrary to what all theory and experience would suggest.
That Amazon wasn't acquiring it for it's business acumen and was actually acquiring it for some secondary purpose (i.e. market consolidation, data extraction)