Exactly. Al Davis might have a friend in Indiana who tipped him off about the kid, and Al sent a scout to watch every game, talk to him and his coaches, his high school coaches, watch practices, etc. So Al Davis may have been able to say yes, this kid indeed carries a second round grade. A media member, even Mayock, whom I think is the best, is very unlikely to have that information at his disposal, so it's just illogical to rate an o-lineman who played well at Hillsdale over an o-lineman who played at a similar level at Alabama or Oklahoma. I mean, the year before Mayock had that kid out of Bentley (?) rated his #5 guard in the draft. Now maybe Mayock has a nephew who plays on Bentley and watched every game, but is it really logical to rate a player who's playing against 175-lb future lawyers and stockbrokers the 5th best guard in the country?
Everybody wants to be in on the ground floor of the next biggest thing, and mock drafting is the biggest copycat industry going.
And yes, saying that Belichick should have picked player X over player Y is indeed an implication that the speaker thinks he knows more than Belichick. Simply stated "I'm right, and Belichick's wrong."