I agree with you. However, just because something isn't implied, doesn't mean it's not a good idea to do it. Charity isn't implied, but it's obvious we should do it in order to help people in need.

We all do open source because we simply love it and want to give a gift, like you said. However, whenever people give me a gift, no matter how bad or good it is, I feel it's my duty to at least say "Thanks!"