Marx to Engels on Darwin:
"Darwin's book is very important and serves me as a natural scientific basis for the class struggle in history. One has to put up with the crude English method of development, of course."
The letter you posted is a hoax.
So again I say by implication you are a follower of Hitler because you are a Christian, and Hitler embraced Christianity.
Marx did admire Darwin. Darwin did not know Marx. Any relationship you perceive in this was one way. Any link between Marx and Darwin, whether true or not, has no bearing on either the validity of evolution nor on the development of the theory of evolution. It does not change the views or the practices of the scientists involved in any evolutionary field.
I really have no idea why you insist on making the link and then try to convince us it matters.
Don't forget that Marx offered to dedicate Das Kapital to Darwin. Of course, Darwin declined the "honor" because Darwin correctly understood that his biological theory did not translate to proper social science, but don't let facts get in the way of your mindless attempt to falsely imply that Darwin somehow advocated badly-designed social systems.