You got it backwards.
The criticism of Trump and his apparatus is not that they want to investigate, but that they make definitive claims of a stolen election and accusations of people rigging it and committing fraud before they have any evidence or proof to back their claims. That's what's humiliating.

If I suspect that you may have stolen something from me, I should present my evidence to a court and allow investigations to take place. I should not accuse you of being a thief publically and damage your reputation before it is proven beyond reasonable doubt. But that's exactly what Trump is doing right now.

So yes it is not only fine, but objective, to state that their claims are unproven, because they have not been proven yet.