No one is saying that they shouldn't have complained... what some are arguing is that they should have complained directly to Mozilla instead of the Internet at large. By making their complaint (valid as it is) so public, they've risked any possibility that they could get design work from Mozilla in the future. A quick email to say, ?Hey, we noticed that the design of this tool that's in development was copied from our design" would have done the trick. Instead of riling up designers online, this could have been handled much better.