Genuinely curious here. Is it a CM's job to help someone get groceries to their room? I guess yes if you consider groceries "luggage"? I dunno. Maybe it's just me. On one hand, I would expect Disney to help with such a thing if they can because that's what I've encountered with CMs, but on the other hand, I personally would never have expected them to help with my groceries or have asked them to. Especially if it was 3 families' worth of stuff. I would expect those families to be helping. But I've never gotten groceries at WDW so maybe I'm just unfamiliar with how that works? ETA: This does not mean I don't agree that the CMs were being rude or unhelpful. I'm just genuinely curious as to whether this is a common service at WDW.
I don't think it is common. Bringing up groceries that a service delivered to the resort and they were already holding for you? Sure. Going out and getting a large order of anything, I don't think so. In my stays Bell Services has never been the type of service where you walk up and demand they help you then and there. They seem to help in the order of request. That is, if 10 people prior to you need their service, then they will get it first. You are put into a virtual queue. At least to me that seems how it has always worked.