Gotcha. Marxists split Socialism and Communism in terms of stages, seeing Socialism as the transitional status where Capital becomes subservient to Humanity, rather than the opposite under Capitalism. The reason Marxists declare that Socialism is transitional is because Marxists believe there is no such thing as a static system, and as such under Socialism Capital will progressively become more collectivized with respect to its development until there is no more Private industry, at which point Communism, ie a fully centrally planned and publicly owned economic system, becomes the next phase.

Communism isn't the end goal, either. With the advent of Communism, there will likely continue to be further evolutions on societal organization, but we can't predict what that will look like without first reaching Communism and observing its trajectories, just like Marx did when noticing Capitalism's tendency to centralize and predicting the Proletariat would sieze it and use the infrastructure for planning created by markets to bring Socialism and eventually Communism into existence. That's where the "Fully Automated Luxury Gay Space Communism" meme/non-meme comes from, as the stage beyond regular Communism.

The other commenter is likely an Anarchist, insinuating that Marxism is Authoritarianism, and therefore not Socialist, though I obviously disagree with that I don't think engaging them directly would benefit anyone right now.