ESPN is in the entertainment business, Johnny Mac says a lot of outlandish, silly stuff. Controversy sells.
This. A thousand times this.
McEnroe will say anything controversial and contrary to get attention and fulfill his role of being entertaining and 'the enfant terrible' of commentators.
One second he's saying that players should call their own lines, the next that doubles should be scrapped, blah blah blah.
If an umpire calls a player out for a time violation he says that they were wrong, if an umpire does not overrule a call and instead waits for a player to challenge using hawkeye - guess what, they were wrong. Whatever someone in authority decides to do - they were wrong. It is clearly in his nature to be awkward and confrontational and it makes him an interesting guy to be around and certainly creates debate. This extends to opinions on players.
Rafa is an amazing volleyer within the context of his game. However, he is not a net-rusher and does not show true flare at the net. Most people intuitively expect people to be crowned 'the best volleyer' to, you know, maximise their time at the net so they can use their amazing volleys.