[Oztrich Boy]

However, "Darwinism" today means much more than what was written by Darwin,

Actually it means much less. "Darwinism" is just a code word used by Creationists for whatever they don't like.

[Restorer]

Wikipedia: Darwinism is a term for the underlying theory in those ideas of Charles Darwin concerning evolution and natural selection. Discussions of Darwinism usually focus on evolution by natural selection, but sometimes Darwinism is taken to mean evolution more broadly, or other ideas not directly associated with the work of Darwin.

Its use as a code wode by Creationists is limited pretty much to the US.

The ideas of natural selection and "survival of the fittest" were originated by Darwin. Even misapplications of these ideas are therefore Darwinian in some sense.