what is with the 'donate' button?

What is with the donate button on blogs? If you are going to blog and give out information, why would you then ask for money for something that you are giving away in the first place. Sorry for all the italics. I know it is not good writing, but I am irked. The donate button to me is like the passive-aggressive tip cup at the counter at Starbucks. You are so put upon for having to do this dead