How deep of an understanding do you have of these supposed proposed systems? As a leftist, the vast majority of mainstream leftist tendencies have strong theory that specifically deals with what you consider to be their ultimate flaw: an assumption of human good. It’s hard to actually answer for every single leftist Tendency, because you haven’t really given any specifics.
As for your second paragraph, there have been remarkably few countries that genuinely have tried Socialism, and all of them were developing countries. Don’t take this to mean that I’m a fan of Marxism-Leninism, but there are two prominent examples of countries that most would consider did in fact “work,” those being the USSR and China.
Again, not defending the USSR or China overall, but asking for clarification on your definition of working, as they were and are economically strong.
Your point about the top of the tree is, bluntly, extremely bad. You offer no explanation why a Socialist or Communist structure cannot be democratically accountable to any lesser degree than Capitalist structures, and assume absolute power. This goes directly against all leftist theory, even Marxism-Leninism, which is centered on the principles of Democratic Centralism.
Your point about Communism being “sharing everything and owning nothing” is also entirely incorrect, and further proves my point. The entire final paragraph is so divorced from any sense of actual leftist theory, that it can only be a product of someone fully believing a right-wing pundit’s propaganda, and not the actual primary sources for leftist tendencies, to the point where I’ll break down each sentence.
Communism, principly, is a far-future status by which the whole of the productive forces can meaningfully provide whatever anyone wants at any time, and work is done for the pleasure of working, rather than for the necessity of being. As such, it must be built towards over a long period of Socialism, which is chiefly Worker Ownership of the Means of Production. Communism and Socialism are built on the idea of earning what you actually work for, rather than allowing individuals to own the products of other’s labor via ownership of the tools they use. You make the error of assuming immediate implementation of Communism, rather than gradual.
We can partially agree on your second point, but given the actual structures proposed by various leftist tendencies, it doesn’t matter for this conversation, and you’ve yet to prove why.
Sorry for the wall of text! I truly think that you should talk to leftists, actually read some Marx, Bakunin, Kropotkin, Lenin, Luxembourg, and so forth, and actually get an idea of what the various leftist tendencies are actually saying. You don’t have to be a leftist, but you absolutely should understand leftism before attempting to disavow it entirely.
Clodsire