Windy only displays real weather data, not some pseudo "future radar":
https://community.windy.com/topic/26216/Please-improve-the-radar-features?_=1691227723935
It is therefore not absurd to show present and past rain.
Concerning the hurricanes tracking, their forecast is carried out by weather models. But these weather models are not able to accurately compute the intensity of the rain at a place in the following hour, especially when they are updated every 6 hours.