Marxism itself wasn’t necessarily tainted, but his ideas of socialism and communism definitely had a social stain associated with them. So by association it had a black mark.

I think it’s pretty clear that we haven’t seen it for what it was supposed to be, when it was weaponized by authoritarians and then attacked by capitalists. It’s supposed to be a grand thing of the people coming together, not stained in blood.

I think you may have misread what I said there about the reformist part. His ideas were revolutionary for the time, but many of the ideas could be applied by reformist.