What's the problem with Bluray player firmware?

Stuck in a Bluray disk today and was greeted with this:

I have had disks take a minute or more before loading the opening menu so I guess it's good that they give a warning.

Naturally, I went to the update site for new software but why does Sony only make update firmware as Windows .exe files? These images get burnt to a CD for the upgrade so surely an .ISO image would work for all platforms?

I've filled in their web site feedback form and will report back if I get a response.