The house does not always win in online sports books. I personally know some quant minded people that have been banned or backed off from a dozen or more online sports books because they are crushed by any nontrivial understanding of price/probability and arbitrage. They do make a lot of money from people who bet for fun or based on their perceived knowledge of the particular sport.
You just explainer why the house always wins. If they don’t, they will stop taking your bets.
> I personally know some quant minded people that have been banned or backed off from a dozen or more online sports books
That's the house making sure that the house are always the winner.
Good video on this:
https://youtu.be/XZvXWVztJoY?si=to8qYcXuBT2xAaIz