When the stakes are high, everyone wants to pick weaker opponents. So the players against whom you want to play don't want to play with you. In the end everybody will have a difficult time starting a game.
Makes perfect sense. It's to prevent people from solely trying to skim off the lower targets while ignoring the tougher ones. It has multiple benefits. One, it makes impressive folks more likely to find someone to play with them. Can't just ice them while seeking out lowbies. For two, it keeps lower/less experienced folks more likely to host games, since they wont effectively be redlighted. Thirdly, it keeps a semblance of fairness in the coin games which lends the coin value more of a real weight.
If you want a game with a certain person, that's always an option and there are methods of exchanging coins if a bet is made on the outcome, but that's not the same thing as a random pool.
To some extent, yes, it is a gamble in lieu of opportunism, but that's part of the point of the game: to match up in a situation that starts with uncertain outcome and continues until the outcome is certain. If you already know you're going to win, there's no game being played at all, just colorful little pictures being filled in. Might as well watch paint dry.
The closest thing in non-coin is probably the random teams/the folks who have their profile information hidden. It is indeed unfortunate that they don't have that system as an option in the regular games (if not as a default)
In poker they call it 'bumhunting' where people want to play weaker opponents and ya it's not a great thing and ya everybody complains about but in the end you get more games than if you make it blind since a lot of people wont play if they have no idea who they will play against.
Maybe Warlight is different and people are willing to take that chance but I wouldn't do it for any meaningful amount of money.