[silvestrov]

Money. They're in for the money.

a) Even if it is only 5%, it is almost pure profit for Oracle. Many big companies would like to expand 5% for almost free.

b) The decision maker might run mac. No mac support, no sales. (One of my customers is like that). This is similar to the "American’s with Disabilities Act" which requires accesibility even though less than 5% of the users are disabled.

c) 5% is the average. Many companies aren't average, e.g. universities and research based companies.

[archgrove]

Your point (c) is the most important, in my opinion. I work in computing theory research at a major UK university, and well over 50% of the desktops I see used are Macs, and about 80% of the laptops. Many of our undergraduates also use Macs. A working Java implementation is quite important for this area - both for Apple, to ensure we keep buying them and Oracle, to stop people just saying "Well, we don't use that much Java anymore, let's just drop it".