I all it "The Steeler fan denial principle." A certain % of fans just love to believe whatever PR the team sends out there and defends it all day long. Those fans can't, or refuse, to think for themselves. As far as the specific case you bring up, they will all clamor for the "but Warren gets his higher ypc mostly on 3rd downs," which is of course just not true, but they stick to repeating that endlessly regardless.
Some fans just need to buy whatever the team is selling, whether it is about the worst OC in NFL history or a head coach who hasn't won a playoff game in 7 years, giving up 40+ on average in his last 4 attempts.