The cheating was so massive and obvious it's as if they didn't care if they got caught.
I figure they were in the position of having to roll the dice. No way to beat Trump on the square. I guess they figure their allies in the deep state, FBI and department of justice, would cover their flanks if they had to withdraw. And watching these last four years I would say that was a rather safe bet.
If you really have nothing to loose you might as well try, right?