I really want to know where you got the idea that the left advocates for "racial essentialism".

Maybe there are some twitter "leftists" who think that way, but that's not the way any prominent leftist thinker or politician discusses race. The left is very clear that race is a social construct and there is no such thing as "racial essentialism".

Honestly I question how much of a "lefty" you really were. The way you discuss these issues sounds identical to a right-wing understanding of the left.