The problem is that betting in a bad outcome incentivices you to exert your influence, even if extremely small, to make that pad thing happen. If you are predicting a hurricane you have no inflence at all (I think), so no harm. If you are predicting a war, you may have miniscule influence (which given enough people can grow to be non-insignificant. Also some people actually have more than miniscule influence in such events (and they can also bet on these markets).
Basically the problem is the similar the fixing matches in sports betting.
The problem is that betting in a bad outcome incentivices you to exert your influence, even if extremely small, to make that pad thing happen.
If you are predicting a hurricane you have no inflence at all (I think), so no harm.
If you are predicting a war, you may have miniscule influence (which given enough people can grow to be non-insignificant. Also some people actually have more than miniscule influence in such events (and they can also bet on these markets).
Basically the problem is the similar the fixing matches in sports betting.