If it's "nit-picky" to take exception to someone telling me I can rip out AD and my Windows back end infratructure, and put in OS X servers and my Windows network will work just like it did before, except it will be easier and cheaper and now I can have Mac workstations too.
When did I say that? I said OS X licensing is generally far cheaper than Windows and with generally equivalent or even better functionality. That is absolutely true. I said that whether it is advantageous to switch depends on each specific case, also true. If, with an honest evaluation, it won't work for you, then fine.
You are the one who has been trying to lock the general concept down to specific cases where it may not work to try to disprove the general truth -- that OS X is a better value than Windows.