Given what Marx and Engels were like as people, I believe it's really just the logical ideological descendants--Marx and Engels were part of the intellectual class, the that-era version of the Hipster SJWs who majored in Useless and idolized the laboring classes, but got very weird about shit when you asked them to *horrified gasp!* work with their hands for a living!
Having studied the rise of fascism, it's pretty telling that the Left chimps out when you remind them of the basic truth that fascism and communism are twins--most of the 'smart' bets in the 1930s were that capitalism wasn't going to survive the Great Depression, so...pick your preferred flavor of socialism, national or international. Conservatives at the time favored the national one, because huh, Lenin and Stalin from the international side were stacking up bodies of people who were getting killed mostly because of their class origin.
Then WWII rolled through and it became pretty clear that the scale of socialism wasn't what made the difference here.
Even if Kevkev had gone to a school where they'd not santized out of the textbooks this kind of thing, he probably spend too much time in the sped class to learn any of this. So he probably just sees "Oh it will give me free things and not ask me to do anything of any use to anybody! Sign me up!"