It’s not free money, it’s high risk with a net positive expected return. Any significant profit would carry an irresponsible level of risk. Significant profit without significant risk would take many bets, which means sustaining the accuracy advantage over broader subject matter, which means lots of time spent, which means it’s time for money, which is just a job.
Suppose I gave Provost 5% chance of winning the papal election. Then I would have been more accurate than Polymarket. But I wouldn't call betting on what I perceive as 5% chance of winning "making free money"; from my perspective it would still be a wild risk to bet any significant money on that outcome.
There was a horrendous problem with gambling on the election at one point. I believe the most recent episode of "Tasting History with Max Miller" covers this.