You are really right. It is impossible to make a 100% forecast for a specific cryptocurrency, for a short or long position. Even experienced specialists who make forecasts in the cryptocurrency market, practically only 70 or 75% of their forecasts are true.
Just want to clarify things here, those specialist you are talking are not really expecting a 100% chance that their forecast will happen. Their predictions are based on what they have seen in the charts. They have a basis on those forecasts which is valid and reasonable. That makes sense compared to those people who will just say a forecast that tomorrow will be up or down.
I'd rather follow that idea compare to doing a suicidal move based on my instincts to minimize the risk of losing.
In the end, we have our own way of what's the strategy should be used.