Fair point, and taken. Interviews are a two-way street: the candidate should ask about everything that matters to them, and the company should ask about everything important they want.

To avoid situations like this, it's best not to assume anything unless you ask first. Windows is the de facto standard in business, yes, but not everywhere and not in every industry.

If your work OS matters to you enough that you will pass on the job if you can't pick, then you should ask. I would not want to hire someone who will be miserable in the job. And as a middle manager I probably don't have enough pull to make an exception just for this guy anyway.

Rock stars play by their own rules and they will get whatever they ask for. For the rest of us, we just have to take what we're issued.