If Marxism is a descriptive theory rather than an ideal (i.e. if Marxism is based on physical reality and ignores identity or "feels"), then we should be concerned with the results that attempts to implement it actually produce--which in each and every case, has been a horror that costs millions of lives, and often tens of millions.

EDIT: It's also worth emphasizing that, according to the article you linked to, Lenin regarded state capitalism as the second-to-last step in a society's transformation into the Marxist-Lenenist utopia. This is important, because even if it's not "true socialism", it's not a complete aberration of socialist ideals, either; it's a necessary step in the process of socialist revolutions. Consequently, it still lays the tens of millions of deaths of Russians, Chinese, Cambodians, and Venezuelans at the feet of socialism.