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.)
The GNU toolchain (or whatever) is licensed to run on any hardware that you can possibly use it on, which will often be cheaper and more accessible than a Mac. Xcode requires Mac OS, which is only licensed for use on Apple hardware.
You can buy used Apple hardware fairly cheaply, but I think that post still has a point about relative cost.
Maybe nobody will see this, but consider this thought experiment: You have a replicator like from Star Trek, which can make any computer that exists now, at zero cost (say it uses garbage you were going to throw away.) Presumably if you copied an Apple machine, it would not legally be a true licensed Apple machine, for the same reason that making unauthorized byte-for-byte copies of digital files does not create additional licenses to use them however you'd like. If Xcode's license requires licensed Apple hardware, it can't legally be run on that machine. On the other hand, FLOSS compilers could run on that, or on a free/libre hardware design that is not even in a grey area to replicate.
While the analogy is maybe a bit silly or different than what was originally said (interpreting "free of cost" more like "libre"), I think it illustrates a real difference that is relevant.
(Btw, I don't actually know Xcode's license -- maybe it only needs Mac OS for technical reasons, not licensing reasons, in which case it could legally and practically be run on any sufficiently correct Mac OS emulator.)
That's not his argument. His argument is that an apple computer is required for Xcode. An apple computer is a regular computer except that it costs more and comes with a bundle of software. Xcode is in the bundle. So... The price is indeterminable but definitely not $0. He hedged specifically against your reductio ad absurdem by mentioning the price difference.
The argument was made against the statement "Apple gives Xcode away for free."
They do give Xcode away for free. I didn't think that factoring a modern development computer into the price was a reasonable stance to take against that line.
Mac isn't a modern development computer. It's a very specific modern development computer, and not necessarily the best in terms of quality/cost.
We're getting unnecessarily deep into dissecting this single line anyway. The original poster's point was that Apple's hardware and software ecosystem, while of great quality, still isn't the "bicycle for the mind" because it's terribly locked down.
Why does it matter that the money goes to the same vendor?
The argument is about whether the software is "free" or not. This only involves the cost to the end user. It is not concerned with where that money is paid.