In fact sports bodies are complaining of exactly that being the case, and in much more obscure leagues than Major League Baseball (whose pitchers are presumably accustomed to, and compensated for, the hazards of celebrity):

'Decapitated bodies, death threats, that's our daily life': Tennis players, helpless targets of angry gamblers [ https://www.lemonde.fr/en/france/article/2025/12/08/decapita... ]

https://www.wtatennis.com/news/4288181/wta-and-itf-release-a...

When the vice industry kept gamblers mainly confined to their own community, it was ugly enough (see the “people with pipes” debt collection trope you refer to). I don’t care too much about how people get their jollies. But I don’t see much good in letting vice behaviors and motivations slop out onto the wider world uninvited.

To your question, then: I’d draw the moral line at “don’t base forecasting gambles on any indicator produced by someone who didn’t agree to be used that way.” If I—as the entity or constituency who incurs the cost to produce an indicator—want to hire the prediction market to run bets on it at arms’ length from me, fine. If not, no.

The burden should be on the gambling interests to prove they’re contributing value to a specific domain, not on everyone else in every domain to prove gambling’s specific negative externalities.