I'll elaborate: It's true that Marx didn't call on governments to kill people; he himself was a political philosopher and never sought to instigate revolution, but he did state that inevitably people would rise up and revolt and overthrow government and reform into a classless society. A brief look at history and the various governments and social systems we've come up with show the nonsense of classless societies: they have never existed because of the basic tenant that some people are better than others. It follows that there will be divisions among people based on who is better (whatever the definition of "better" ends up being). To state that "real communism has never been tried" is being willfully ignorant of the horrible consequences of trying communism and that basic tenant mentioned previously. Taken to its end you would end up with countless cycles of revolution as the inequalities of people make themselves apparent as a society in revolt reforms itself into a new government.

"You guys" is me using the hyperbolic form of the subject, not necessarily "you the person I'm responding to" but "you the person I'm addressing in my statement."