I like the show and I like the show's message. It's the only "modern" (read, post 1970) adult TV show I let my kids watch, without any qualms. And I like Phil. I aspire to be a curmudgeon like him.
However, the Robertsons get paid each week for doing what amounts to a 30 minute commercial for their business. It's watched - not just tolerated like a commercial, but really watched - by millions. Far more than any paid advertisement would.
Redneck doesn't mean "dumb", Jack. :-)
Ignorant and stupid are two very different things. I do not believe any of them are either one.
If couldn't stop myself from being excessively literal, I would observe that it's likely that there are many subjects of which various members of the Robertson family are ignorant, just as there are for every living human being, even Thomas Sowell. We all don't know much more than we know.
Phil is my absolute favorite on the show. Calm, measured, wise, but not in any particular hurry to place himself on display. I don't think of him as a curmudgeon; I don't recall ever seeing him flustered or upset, even when his old chair was sold he took it in stride. I particularly enjoyed seeing him and Kay renew their vows.