If your program is free (as usually with open source), you have a lot of 'customers', which all feel they are entitled to support. Pulling the information you

If your program is free (as usually with open source), you have a lot of 'customers', which all feel they are entitled to support. Pulling the information you need from users to fix a problem can be quite some work. This decreases the time available for development. That's all. Hence "DoS". I don't see any belittling in that.