Maybe the difference lies in permission?
It seems like a better situation all around when you are not dependent on legal agreements and "may I look at this source please?". This also does not guarantee that your fix will be used (though it is quite likely to be).
What if you are a smaller company than Samsung? Maybe Microsoft will just ignore or outright deny requests to see the source code.
I think the ability to see code and make/publish changes to that code independent of permission to do so is an important right.