What trial? The shooting was ruled to be justified by the DOJ and Capitol Police so there will be no criminal charges to try. And the officer in question can't be sued because like all police officers he enjoys limited immunity. Babbitt's family can sue the Capitol Police but the identity of the shooter may not be relevant to that suit.
Could have taken 2 steps and pushed her back through.
True. But there has been case after case over the last couple of years where officers could have done something other than shoot an unarmed suspect but instead killed them and were never charged. Babbitt's case is just another instance.
Ashli Babbitt was killed by Lt Michael Leroy Byrd, who accidentaly discharged his Glock. He was careless, and needs to be charged at least with criminally nefligent homicide.