ADDED: The disconnect isn't really that surprising. Historically, why would you trademark something if you had no intention of selling it? How would it even get broadly distributed if you were just giving something away? Obviously, those conditions don't necessarily apply today even though you have the same issues of confusing different goods and services that have always existed. As for the law firms, it's mostly an argument that if you want an IP lawyer in an open source context, you probably want one who actually has experience in the area.

"Use in commerce" is more about, are you actually making things with it, are you publishing those things, are there people interacting with your product under that name, etc. The fact that most commerce involves money changing hands is incidental.