And who fueled the profits? Gamblers?

This instance is what you could call a scam, maybe even fraud. But in the absence of manipulation or insider knowledge predicting the weather is pretty close to gambling. As is "does bitcoin go up or down in the next five minutes" or "how many tweets will Elon Musk post in the next couple days" (all real bets on Polymarket)

Yes, gambling. That's literally what gambling is, a scam.

A lot of gambling is a scam executed form profit. I call it a scam because it's not always fraudulent, it's persuasion and a dash of misleading info. Often one party unduly influences the outcome or has information that the other can't have. Whether it's corruption to predetermine the result of a match, or knowing that the star player will miss it, or a gambling machine that suggests a higher expected payout than the real one, or even a casino's rules that arbitrarily decide whether your win was legitimate or not, in practice the industry is more scam than legitimate business.