It still is a fact. The statement is implicitly about the relationship with Germany at the time of the statement. It is not a claim that the relationship will stay the same for all time forward.
"In 1992, the Germans were our friends."
Facts don't change. Poorly-worded, imprecise, incomplete statements can be misunderstood, though.
> 1942: “The Germans are our enemies.” That was a fact.
And it will not cease being a fact that, in 1942, Germany and whoever were enemies. Nor that they became friends later. It's possible that they will be enemies again in the future. That wouldn't render the statement about 1992 non-factual.
I'm not even going to bother with the mayonnaise, since that's just founded on a willful misinterpretation of the original comment.
We can get really, really certain about some things. If a superforecaster (or anyone for that matter) gives 95% certainty on an event occuring and he or she has frequently made similar predictions with 95% accuracy, the event is likely to occur. It's still uncertain, but not by very much.
"Donald Trump is president". It's uncertain, certainly, but I still feel comfortable calling it a fact. Are you talking about misuse of 'facts are unquestionable' to apply to statements that aren't as clear?
I hate mayonnaise. I guess that makes me “wrong.”
and "facts are indisputable."
1942: “The Germans are our enemies.” That was a fact.
1992: “The Germans are our friends.” That was a fact.
Facts change. Nothing in the universe is indisputable.