Sanders has always like this. In fact his policy is quite different from the "mainstream" Domocrats and always has been.
"Liberals are struggling" "this as a platform" if you try to conclude what the "platform" is from Sanders' opinions you'll be quite far from the truth.
Bernie Sanders is not a democrat or liberal, he is a democratic socialist who specifically runs as an independent.
That normal liberals are so deeply associated with his ilk by the national electorate to the point Harris was considered more radical than Trump is a whole can of worms in itself.
What even is this as a platform? Yes, wealth inequality is bad, but what exactly does this do to solve it...?