Hey guys!
So the original post doesn't really seem to be talking about Marxism, which was no more than a philosophical lens through which to view history. It's actually talking about the Far Left in general, and a broad range of ideas associated with the Far Left.
I'm someone on the Far Left who subscribes wholeheartedly to essentially every single thing OP went on about, and so I feel comfortable saying that the thing that my ideology offers is a liberation of human society from the chains of class structure, which inherently develop divisions along the lines of "biology", which in reality means the lines of socially constructed concepts of certain biological traits which really result in only marginal differences of ability. I mean it seems to be a criticism of anti-racism and feminism, as well as socialist distribution of wealth, three things whose purpose is quite clear: respectively, the destruction of racism, sexism, and the class-based distribution of wealth.
The grounds of OP's disagreement with these systems being destroyed seems to be the falsehood that they are more efficient than a theoretical society lacking of them, which is an outrageous claim to make because there has never in human history been an example of a society, global or local, that lacks these constructs, since pre-agricultural hunter gatherer civilization was predominant as the organization of human society.
So in short what we offer is a better world for most, a less powerful life for others (those in power, usually), and an idea that most folks who would probably be on this website would not be willing to grasp.