For example, even in a fair game the house will eventually take a gambler's bankroll provided the house's bankroll is practically infinite [1]. That's a thought experiment, but it works in practice when you are dealing with gambling addicts that won't walk away from the table.

Secondly, those gambling addicts, or "whales" as they call them represent something like 0.15% of players bring in 50% of the revenue [2].

And lastly, I would have agreed with you a few months ago, before I heard this story [3] on NPR about how Big Fish was targeting people and using predatory practices to keep them on the game. It reminded me of a twisted version of AOL's customer retention practices that they were sued for a decade ago.

There's also the whole notion of casinos/gambling disproportionately impacting low income communities and how you can't start a gambling business without tons of capital, so it serves as an efficient funnel of money from the poor to the rich. And it's really naive to think that someone going broke affects that person alone. God help them if they have a family.

[1] https://en.wikipedia.org/wiki/Gambler%27s_ruin

[2] https://www.forbes.com/sites/insertcoin/2014/03/01/why-its-s...

[3] https://www.pbs.org/newshour/show/how-social-casinos-leverag...