I see what you are saying. I agree Neville has a bias, it's just in the opposite way to what he actually feels..Biased towards Moyes (probably because of his brother). He didn't even try to make an equilibrium that the blame should be shared between Moyes and the players, until recently he acted like Moyes is the best thing to have happened to United this season. Which is far away from the truth.
If he had only tried to blame collectively all the players and Moyes (and his staff) it would have been probably ok, but he acted like players are shit and don't give a shit, while Moyes is a brilliant manager which is fighting against the world.
He almost "pretends" to support the teams United are facing when commentating, as he is massively over compensating for his red-tinted glasses, but it's more than practically anyone else has tried to do so that gets a big green tick in my book.
And as you say, he blames the players constantly and backs Moyes to the hilt. He should be loyal to the players as they are his friends and former colleagues, but he throws them under the bus for the sake of good journalism. Perhaps there is the "brother Neville" factor there too.