Thats why they support modding so much, they basically outsource testing and bugfixing to their community of eager modders.
Good point. It could be a lot worse. They could not do mod support and still release broken buggy games like many other publishers do.
How can we use C# in a responsible and FOSS way? A huge advantage of C# is that it can't run into include order problems like C++ can. This makes it easier to make better object oriented games because the object structure can be more useful and you can get better results even if your object structure planning wasn't as well thought-out.