You should probably let these guys know. It's very unlikely to be intentional as spam reports or blacklists are much, much more harmful to email operations than

You should probably let these guys know. It's very unlikely to be intentional as spam reports or blacklists are much, much more harmful to email operations than an unsubscribe. For these small mom-and-pop style online storefronts they are almost certainly using a vendor or plug-and-play system and likely don't even know enough to know something is wrong.