Traditionally it has not been, but the current CFTC says that 'prediction bets on sports' ARE under their purview. This has not been fully challenged in court, though.
And by your argument poker or backgammon would not be gambling either.
They aren't. A sportsbook explicitly sets lines and you are betting that the line they set is incorrect.
They charge trading fees.
There’s no house like in sportsbooks.
https://straighttothepoint.substack.com/p/you-cant-have-it-b...
https://www.sportico.com/business/sports-betting/2025/kalshi...
They just don't make any money off it.
This is Don Jr's consulting fee at work.