People need to know why these squishy Rinos are doing this. It's not to support Trump.

It's to help Biden in the Primaries. If they can keep Bernie and Warren tied up in the Senate, it' helps Biden. And Romeny has his own Ukraine skeletons to protect.
He wants Trump to lose and feels Biden is the best shot. He can't be obvious in his nonsuppport of Trump, so anything he can do,to help Biden he will. This was Nancy's plan also. To get enough support to call witnesses to prolong trial. That's why she delayed, to get close to caucus time and get votes for witnesses.

So obvious.