Whilst your second sentence is true, belief that Trump would be declared the winner of the election even after he lost is something highly skewed towards people inclined to believe Trump and Trumpists' claims about electoral fraud,- Mike Pence having the casting vote etc.

And the most obvious reason why not enough unbiased cryptoenthusiasts were tempted to place massive bets on something already decided to correct the odds was suspicion that the oracles might be too biased in favour of Trump being the real president for them to be sure of the easy profit the odds implied

There's another possibility, which is that "Crypto people," are another isolated pocket separate from any mainstream faction, that come up with their own weird beliefs for their own divergent reasons. An uncorrelated niche faction would be expected to go closer to one mainstream faction's beliefs over another's about half the time.

Right, and as mentioned in the article: The markets were guessing Trump would win after he had already lost. If that's not evidence of a political bias to you I'm not sure why.

When hurricane forecasters predict that a hurricane will strike a city, would that be evidence of their pro-hurricane bias? If they were consistently overeager to predict hurricane strikes, would that be evidence that they supported hurricanes, or merely were overcalibrated to predicting them?

If a forecaster saw a hurricane make landfall in Texas and still gave it a 15% chance of hitting Alabama, that'd be pretty far beyond simple poor calibration, and I think it'd be justified to ask some pointed questions about why they're so dedicated to their bad prediction.