When both sides of the dev team BOTH want Macs, and can provide both technical reasons (which you skipped there) and have a personal preference for it, then it seems silly for the department supervisor to NOT go along with it.
Plus, the corporate Dells + support plan + etc... are pretty close in price. And our department was responsible for 2 billion+ in corp revenue, so a few Macs are a small price to pay.
At one company I worked for, the IT guys hated the macs.
The first reason was that they ended up costing twice as much to match the configurations (extra memory, the requisite software, etc).
The second and more critical reason was support. Apple just wasn't up to the task of handling a call from someone with somewhere between half a dozen and 100 macs at once.
The first reason has been changing in Apple's favor since, and the last time I checked around 4 months ago the cost was pretty much even.
Plus, the corporate Dells + support plan + etc... are pretty close in price. And our department was responsible for 2 billion+ in corp revenue, so a few Macs are a small price to pay.
I'm glad you weren't supervising our department:)