But that argument simply books down to "more expensive computers cost more". True a Linux computer might cost $500 and got $0 more you can program on it. A Mac might cost $800 and for $0 more you can program on it. The marginal cost to develop is the same. But I could easily spec up a Linux workstation costing thousands of dollars. Macs being expensive doesn't make Linux computers more expensive, it doesn't raise he costs for anybody else. So who exactly is being harmed here? I just don't really see what useful point is being made.

If we follow your argument to the logical extreme there is no such thing as free software because the computer to run such software almost always costs money?

(Unless you receive a computer as a gift or it is freely leased; but then that applies to Macs as much as any computer.)