Most people have no idea what Bonjour is, or that they are even using it. By making it an easy to find option, it increases the chance a novice computer user will turn it off without realizing the impact it will have on their Apple TV. This causing them to either return the product, or call Apple support, incurring cost. Thats at least my theory, that it's a business decision. I can't provide an exact reasoning behind it.

As for "4 or 5 processes", they wouldn't impact performance on a modern machine. No more then the 50-60 or so processes Windows 7 runs out of the box. I'm not necessarily defending the decision, but Apple brings the tech they need to run on Windows platforms and provide the same services they do on the OS X side. Exactly the same way Microsoft Office and the Video for Windows codec installs other Microsoft components into OS X to function properly.

As for enterprise deployment, Apple sells this somewhat popular smartphone, and even 10% of Microsoft employees use it to access their work e-mail.