Actually disagree with most of that. I think the bear hug on Maguire was about as clear as you can get timing or not, he had him pinned and bundled to the ground. Simply blatant. The shirt tug by Stones goes on at just about every corner kick in every game, it was quite mild. A light tug should not lead to a player's legs collapsing beneath him. Blatant bullshit honestly. At the very least they're both penalties, if you're giving one you had to give the other. If you didn't give the first, this should not be given either.
Your other point is really a point on referee and player psychology (which might be accurate but is misplaced) and I personally think if the Maguire foul is given (correctly), it sets a tone that you can't fucking bear hug and wrestle players to the ground. The ref says "this is a penalty and I won't stand for this type of fouling in the penalty area on corner kicks". Hey presto, the wrestling mostly stops, instead of continuing all game.
It's weak as piss officiating.