I have a "funny" feeling Miguel probably turned his back on the community because of the zealotry and hate spewed from the community at large. Some of the comments AND moderation are embarrassing!
The GNOME Desktop at version 2 was great, I was a fan for many years and I'm grateful it exists. I didn't like KDE during that time (found it too clunky - just my humble opinion - I like it now!) .
Personally I think the "Desktop" as it stands today is bloated and way too complicated now and I say this in particular for KDE and GNOME. I'm currently using XFCE.
The Mono project was a response to Microsoft's "invention" of the .net platform where "all Windows software will be based on .Net". Potentially there would have been no way to write cross-platform software for Windows. Thankfully not much of a threat now. I used Mono years ago and enjoyed coding for the platform.
Miguel has started Xamian and the company offers cross-platform development tools which is great but I can't afford the $300 yearly subscription and Linux support for the "platform" is noticeably absent. A damn shame really. I would liked to have evaluated it.
Also, one of the main "features" of Linux is the existence of many distributions of Linux. I started with Slackware then Redhat, Mandriva, Debian, gentoo, Ubuntu and now Porteus. They've all served me well over the years because each one filled a particular need at the time.
I'm no zealot and I use what works for me. Generally I use Windows for gaming & Linux for everything else. I'm considering buying a Mac because I want to develop stuff for iPhone (I actually own an SIII) and don't like the idea of Microsoft locking down the bootloader on a "PC". I know Apple do this too but at least their OS foundation is based on unix.
Miguel is entitled to his beliefs and opinions. He may have made mistakes but nobody is perfect.