Holy crap, you really think like that?
Here's the thing: let's go with your mindset, and think that MS is just waiting to file patent claims against Mono, because they hate Linux. They're just waiting...
MS HAS A TON OF PATENTS. If they want to try to screw up Linux, they can sue over probably 50 other things. So banning Mono doesn't accomplish your goal. So quit pretending that it does.
What about Samba? Why is that fine? Let's ban that, too. What about PDF? That's an Adobe-owned format, let's get rid of that, too.
Open Office supports VB, the devil's language as you mentioned above. Now how is that any different from Mono? Should we go ahead and take that out, too?
You should be more honest and write: "I don't really understand what C# is, and I hate Microsoft. I don't want anyone using apps written in C# unless they wrote it themselves. If this were the 1970s, I would be saying the same thing about C and how everyone should continue writing apps in Fortran and Cobol, like God intended!"
How exactly is using an implementation of a published spec "repeating the mistake of using MS Windows"? That's just 100% incorrect, and if anyone in this debate was interested in talking about the truth rather than their blind ideals, I wouldn't be the only person calling you out on it. Don't lie to try to win a debate.