The article is insinuating that inside information was used to make money on the specific date:

Now there are suspicions that other insiders used the Iran strikes to get rich. Six accounts on Polymarket reportedly won approximately $1.2 million by predicting the U.S. would launch a strike on Iran on February 28, according to CoinDesk.

The other example is more convincing though:

When the U.S. captured Venezuelan President Nicolas Maduro in January, an individual with a relatively new account pumped $30,000 into a bet that Maduro would be ousted. Hours later, the Trump administration captured Maduro, earning the gambler more than $436,000.