What was the timing though? December 2016. The election was already over. And the FBI already had the dossier. They helped commission the dossier. McCain may be scum but don’t let the guilty parties off the hook by blaming their crimes on McCain.
It's not an either-or proposition. Pursuing a guilty McSlime does not logically mean other guilty parties are being let "off the hook." Unless your name is Megan McCain, this doesn't make sense.