A lot of those support demands are created by how Linux users end up using Windows, which makes Windows seem more problematic than it actually is.

One thing that makes Windows look bad from the perspective of a Linux user who dual boots is the system update process. It hijacks the machine and starts a reboot cycle that is tricky to get out of until it is completed. This is not a problem for most Windows users because it happens when they shutdown or when they choose to reboot. Unfortunately the Windows system update process typically starts when a Linux user tries to switch from Windows to Linux in order to get something done, then resumes when they try to boot back into Windows to get something done.

Another issue is software updates. In Linux, this typically managed by the distribution and happens in the background. If scheduled, Linux users will never even notice the update process. If handled manually, Linux users choose when to perform the update rather than having software prompt them when they are trying to get work done. If that Linux user is dual booting, they will be particularly prone to noticing that issue since their Windows software is performing update checks less frequently. As such, those dual booting Linux users will see the update prompts much more frequently (relative to the number of times they start the software).

Yet another issue is that many Linux users come from older versions of Windows and are typically comparing it to newer versions of Linux. Microsoft did a great job of addressing Windows' issues during the XP era and with the release of Vista. Unfortunately, many Linux users aren't aware of those issues since they came from XP, early versions of XP, or even versions of Windows prior.

I do believe that most Linux systems present fewer support demands because of how Linux is designed. On the other hand, I can't help but admit that many Linux users make Windows sound worse than it is because their often limited interaction with the OS will consolidate a lot of infrequent Windows annoyances into one session.