Hostile feelings about mega-yachts aside, I think the 40 footer was likely in the wrong by failing to anticipate the wind shadow and dirty air cast off by such a behemoth on its lee side.
There are admittedly less massive barks (200 feet or a bit less) and other tall ships here in Toronto that more or less motorsail around the Island while selling liquor, box lunches and digital camera batteries. I know a lot of people who sail on the windward side of them as they do a sedate 5-6 knots, which encourages 30-40 footers to "race" them, providing mutual photography opportunities and good fun for all.
But everyone knows they can't maneuver well or quickly, and they don't get in close period, and stand well off on the windward side to avoid the dirty air (literally...a couple of these things run 2-stroke Detroit Diesels...feh...)
You stick to windward, and you don't play chicken with their bows. I pull ahead three of THEIR lengths (600 feet) before I ease sheets and cross their bows, and in crowded conditions I will give a sound signal.
Blaming the mega-yacht in this case is like blaming a dock for being in the way of your gybe. Not liking the fact that a mega yacht is plying back and forth in your cruising ground like a 14-knot island is a different argument, I think.