Richard is seen as one of the most brilliant people in the opensource world however also seen as one the hardliners in the opensource world who is not willing to make any compromise on his thoughts of what opensource is and should be. Some people think he is reacting to strong and state that he has become to much of a hardliner. I do however agree with him on this. Linux should be complete opensource and by adding a application like Tomboy we are compromising to this thought. Linux should be a platform that you can change to your liking and by having a dependancy to closed source you loose this ability.
In my opinion you should be able to pack linux on a laptop, get all the sourcecode, and move to a deserted island and be able to do anything you like to it without having the need to contact anyone. Complete freedom and not depending on any other person. By adding tomboy to it you are depending on Microsoft and to the thinking of Microsoft. If you need a function changed in .NET for some reason you will have to wait until Microsoft decides to do it, if they ever do it. And not only is this the case with .NET it is also the case with for example C#.
it is not a issue of opposing against a language, everyone should pick the language he or she likes to use. It is opposing against mixing licenses in Linux. As Mono is depending on .NET and .NET is not GNU/GPL compliant it should never become part of a linux mainstream release. If you really like it you should have the option to implement it however I would vote against it as it is not GNU/GPL compliant.
If you coding in for example Python and you need a special part of the compiler changed for some reason you do have the ability to go to the Python website, check the sourcecode, change it and make you own version. That is complete freedom as it should be. Not many people will do it however you do have the option if it is really needed. As some person from the US army once stated about systems that would make it to the battlefield, “if we can not hack it we do not pack it” and that is a very true statement. If you do not have the option to make modifications to it when the situation calls for it it is useless.
So, placing Tomboy in Debian and by this making yourself depending on Microsoft is a very bad move. Richard can be seen as a hardliner however I can only agree with him on this part.