The real issue here is that if you tell some gmail user to contact their e-mail provider to resolve delivery issues on their side, like this, they'll just stare

The real issue here is that if you tell some gmail user to contact their e-mail provider to resolve delivery issues on their side, like this, they'll just stare at you, not knowing what you're even talking about. It's like there's an assumption that gmail is perfect, and the problem is with the sender. Even if that was true, a normal mail hosting company would at least tell its customer why the mail is not being delivered, so that the customer can tell the sender what to fix. The gmail recipient is never exposed to this side of google. So they don't know what a nightmare comapny it is to communicate with. Why should everyone and their dog be solving gmail users's problems with receiving messages? It's such a demented system. It should be the other way round. Recipients, via their provider should be solving their issues with spam filtering and blocking. If the gmail user would be blocked by my mail server, I would not tell them to go guess what's wrong, fix gmail, and to have fun. It should not be acceptable the other way round either.