What’s the objection to communism?
The way that communism has manifested in this world (as opposed to some "idealized" form of communism) is the very antithesis of spirituality, for it is the "religion" of materialism: i.e., it maintains that the material world is all there is, that Spirit does not exist.
Such a view is, of course, quite objectionable to anyone on the spiritual path. To such a person, the material world is but a coarse manifestation of Spirit, and is far from being "all there is." More like, it’s "the least there is." Therefore any social or governmental system that actively propounds the material world as the only reality would, to a spiritual seeker, be quite unacceptable.
On the other hand, communism that merely takes the form of communal living, without anyone being dogmatized or tyrannized in any way, or forced to live/speak/think in a certain way, could be a different story.