Thank you for the very long answer! Lots of substance there to answer, which I will, but that will take a while. In the meantime, I want to clear up a few misconceptions and partially affirm a few of your guesses.

(1) You're completely wrong that I haven't read Das Kapital before--indeed it is because I read it before, decades ago, out of a book titled "Das Kapital" (complete with a classic portrait of Marx on the cover) that I call it Das Kapital. I'm happy to switch to calling it "Capital" if that is the modern convention for how to refer to it.

(2) However, I haven't ever studied the labor theory of value in a comprehensive way. I read Marx on my own, and with an eye towards his philosophy not his economics specifically. So it's entirely possible that when Marx repeatedly says things that sound completely stupid in light of real economies, I'm not properly interpreting it in the historical context where certain things from Smith (whose ideas I'm familiar with, but whose works I've never read) are taken as given. However, as I'll get to when I actually respond, I'm not willing to simply grant that this is the context--it needs an argument.

(3) My arguments are my own, not copied from any other source. This is both a strength and weakness. The original post was more "off the top of my head"ish, in that I posted without remembering the details of Marx's writings, but this doesn't mean that the thrust of the criticism is ill-considered (though that argument may have been sloppily constructed).