Here is the thing: about half the time the "newb" will actually be the lower skilled player, but the other half of the time he will actually be more skilled than you. Yes, match making doesn't exclusively match you with retards, on average you will get matched with superior players about half the time.
With that known, you must realize that occasionally the player who is actually least skill will start giving advice to players of greater skill. If you listen to the friendly advice giver and follow his advice, you will lose, because he is giving terrible bad advice. However, the kicker is that there is no way to tell whether you are being given good or bad advice at the time you get it!
So your choice is to follow the advice of players who give it all the time, and lose because of that bad advice half the time. Or you can ignore the advice all the time, and maybe lose half the time because you ignored good correct advice.
Or, this is what I actually do, is you can listen to sensible advice that is given in a polite way while you disregard advice given by arrogant players who have the "do what I say or you suck" attitude. I've found that this is a fairly decent filter, most of the arrogant players who yell at their own team actually fall into the category of player who only thinks he is smart, and are actually giving terrible advice.
Of course I'm not even touching on the cases where you get false feedback. For example, player is pushing a lane, you yell at him to get back. He takes tower, then gets ganked by enemies who teleport in at the last second. You think "oh see, this guy is an idiot, I warned him he was going to die, and look! he really did get ganked! I was right and he was an idiot!" While the reality is, he give up ~600 gold by getting ganked, and earned your team some 1200 gold by destroying the tower, while simultaneously wasting enemy gold spent on teleport scrolls.
I see this all the time, a player does the strategically correct play but he gets called an idiot by team members who can't do basic math.