They stopped support for Studio but allowed people to still play on those machines due to people from places like the Philippines that usually only had access to machines with XP/Vista installed.
Speaking of which, will that harm the playerbase there at all? I remember @Wsly stating he had Philippines fans that would regularly tweet him photos of them playing that still had XP. I also have to agree with his comment regarding the removal of support of Windows XP in particular would slow/prevent the growth in the Asian market and similar regions.