I suspect he isn't going on the offensive so much as there have been an inordinate amount of chain store-bashing posts lately. It's getting old, and could become a legal issue (not saying that it will). To me, that post reads as simply a warning.
At any rate, I don't often purchase fish from chain stores and would recommend buying them at a mom and pop place if you can find one. If the mom and pop joints around you don't sell them, it may be possible to special order. In many cases, I find that the standard of care for fish is higher at local businesses (though this is certainly not always the case), and as such, I try to patronize these sorts of stores.
At any rate, I don't often purchase fish from chain stores and would recommend buying them at a mom and pop place if you can find one. If the mom and pop joints around you don't sell them, it may be possible to special order. In many cases, I find that the standard of care for fish is higher at local businesses (though this is certainly not always the case), and as such, I try to patronize these sorts of stores.