You have to remember that to the apparachiks on the left, there is no such thing as “truth” so there is no such thing as a lie.
What advances their agenda is “good” and what does not advance their agenda is “bad”.
Thus they are total racists in 1920, and totally against racism in 1960.
They are for whatever is seen as useful for their agenda, so whatever position is seen to advance their agenda becomes theirs.
Yes it’s always the ends justify the means with them.