An accurate model can output a 50-50 prediction. Sure, no problem there. But there is a human bias that does tend to make 50% more likely in these cases. It is the maximum percentage you can assign to the uncomfortable possibility without it being higher than the comfortable possibility.

538 systematically magnified this kind of bias when they decided to rate polls, not based on their absolute error, but based on how close their bias was relative to other polls' biases.(https://x.com/andrei__roman/status/1854328028480115144) This down-weighted pollsters like Atlas Intel who would've otherwise improved 538's forecast.