I mean, a ton of people think libertarians are republicans who like weed or democrats who don't like to spend money. In reality, Libertarianism is its own philosophy with a deep set of ethics and morality, a political party, and more. Now I have seen someone make a philosophic argument that fraud isn't punishable under a libertarian philosophy, but more make the other argument. Fraud is violating the contract, simple as.
Now there is the Casino point: There are shitty deals that are presented honestly enough. If you decide to go into a casino to play the craps table thinking you'll win money but go broke, that's straight up on you (assuming fair dice). They told you the rules of the game, and more, everyone knows that the odds are in the houses favor. That's not fraud, that's just buyer beware.
Fraud does occur when someone sells you a house claiming X square feet, and it's Y. A straight up lie. Or more subtly, someone sells you a car, but not the engine, while implying it had one (pictures of a new car, etc).