"compared to Clinton's are no longer "meaningless"...
I don't think so. Sanders hasn't faced 20 years of attacks from all sides and still is the one standing at the top of the Democratic party.
Sanders would be dismantled by the Republicans very quickly because his plans make little sense and he openly declares that he will raise the taxes of everybody with a job...his payroll tax increase, stances on trade, utter lack of foreign policy sense...these are all horrible things and doom Sanders in a general election.
Not only is Sanders not our best chance to win but we don't want him to win.