If you believe all the jurors are not impartial, why wouldn't you want to see the evidence and hear the witness testimony to make a determination for yourself? If this situation was reversed and it was a Hillary impeachment trial with a Democrat-led Senate acting like this, Republicans would be in an uproar and very rightly so. I'd be fucking pissed as well.
I just don't understand how, even if you don't agree with it, folks wouldn't even want to see evidence or hear testimony. And if y'all want Biden to testify under oath, I say go ahead but NOT during the impeachment, that's only there to muddy the waters. Make his testimony and case separate through the relevant agencies and I'm on board