I think the limitation to team "let-people-do-what-they-want-even-if-it's-bad-for-them" is that it's rooted in outdated assumptions about what free will and coercion look like. Broadly speaking, libertarian notions of negative freedom assume a model of coercion with a very small footprint, primarily the threat of immanent physical violence. Similarly, it sees the exercise of free will as a binary action, rather than a spectrum of ability.

We entered this era a long time ago, where psychological insight and computational or chemical power can combine to override people's ability to make free choices. But I'm still not sure there is a widely shared philosophical or ideological framework that has fully digested and responded to these new realities yet.

If I ever see that, I'll tell the dad something

Right, but as exploitive as those things are, they're still regulated and taxed as gambling. The regs may be a joke, but they exist. Like in some places they're required to remind the player about addiction concerns and direct them to help for it, and to fund those programs. And part of the reason that states (and provinces here in Canada) were so gung-ho on the liberalization of gambling is that they take a fat cut.

aside: recreational gambling should require a federal ID with losses tracked online, and if you're down more than 10% of last year's after-tax income you're cut off for the rest of the year, but I assume the Canadian and especially US constitutions rules against doing good things federally make that impossible.