You are mistaken. For every person making a "slightly stupid bet" there's another person who is making a "slightly smart bet". With Kalshi, they aren't the casino who encourage people to make a bunch of bets with negative EV. They are a marketplace that allows one smart person to make a bet with one dumb person (according to your parlance). As long as the markets are fair with no manipulation, things should balance out.

It's like the stock market, where there's always one buyer and one seller. The marketplace, ie. NYSE or Nasdaq for example, don't bias in any particular direction they just being one side together with the other.