Well that's where we'll have to agree to differ.
In my world, a World Champion is champion of a world wide sport that has defeated all comers on a world stage at a World Championship.
To you, as you say, it's a meaningless title that anyone can use as they see fit. And frankly that's a shame.
And what is the point of a title if it has no meaning?
As for your comments about sailing championships, your knowledge is obviously extremely limited. The only competition where the previous winner sets the format for the next competition is the America's Cup, which isn't a world championship anyway, it's a challenge cup.
In the real world it’s just a couple of words. Leagues can name their champions whatever they want. A league could call it’s champion the King of all Siam if they want, they don’t even have to have anything to do with Siam, it could even be a womens league, because it’s their league and they can call it what they please.
Doesn’t really matter what your precious sailing championship did. I guarantee if I wanted to go through the rules I could find a reason why it’s completely bogus to call it a world champion. Except I wouldn’t because I don’t care. I don’t care what any league call their champion.
Really your own argument shows how painfully silly your complaint is. There has never in the history of sports been a world champion that defeated all comers. There’s always going to be some sort of rules system that limits who vies for the championship. And even in sports with a system that has all members of the league play each other at least once, the league itself is artificially limited, and nobody beats everybody. So in your world, according to your rule, there has never and will never be a “World Champion” in any sport, including the one you participated in.