A person or company has the right to cease to work on a particular program; the wrong here is Microsoft does this after having made the users dependent on Microsoft, because they are not free to ask anyone else to work on the program for them."
Microsoft did not make anybody dependent on them, and should have zero obligation to open source Windows XP. There are thriving alternatives to Windows like OS X, Android, Chrome OS, and iOS that XP users could have moved to in the last 14 years.