I can't seem to pick out the argument that you're making here, other than that it begins with an assertion that no one who "really" understands economics can dispute it.
I'm going to guess out loud at it, and hopefully somebody will jump in and help me.
1) In the case of goods or services with minimal marginal costs and large fixed costs in proportion to total costs, you are expected to pay for them.
2) If you don't pay for them you are breaking the law.
Therefore, the argument that if marginal cost is zero on some digital good, then [something number 1] isn't stealing is completely irrelevant to [something number 2].
I'm sure that "something number 1" (referred to as "it") is related to free riding, due to a shared metaphor, and I'm going to assume that it is "a use of that good or service without paying," again due to the metaphor, where a single person took a single train ride without paying.
Does "something number 2" = "whether a use of that good or service is illegal or not"? Because that seems to me to be setting up as a straw man a question that no one is asking, then begging the question with an answer that is identical to your second premise.
I'm going to guess out loud at it, and hopefully somebody will jump in and help me.
1) In the case of goods or services with minimal marginal costs and large fixed costs in proportion to total costs, you are expected to pay for them.
2) If you don't pay for them you are breaking the law.
Therefore, the argument that if marginal cost is zero on some digital good, then [something number 1] isn't stealing is completely irrelevant to [something number 2].
I'm sure that "something number 1" (referred to as "it") is related to free riding, due to a shared metaphor, and I'm going to assume that it is "a use of that good or service without paying," again due to the metaphor, where a single person took a single train ride without paying.
Does "something number 2" = "whether a use of that good or service is illegal or not"? Because that seems to me to be setting up as a straw man a question that no one is asking, then begging the question with an answer that is identical to your second premise.