* Then company A needs to fight the trademark of company B.

I'm not sure what your point is here. Like I said, trademark law is a enforce it or lose it thing: you have to stop people from infringing on your trademark or you can lose it. However in this case, we clearly have a situation where a trademark was issued for a generic term: Coinkite is threatening someone for using a name, btcclock, that Ricardo Cassata came up with _7_ years ago for the same concept, long before the Blockclock even existed. Coinkite chose to try to enforce their trademark broadly when they, at minimum, could have accepted that their trademark should apply narrowly given the fact that it is pretty generic. If the defendant was calling their project a "Blockclock" this situation would be more reasonable. They're not. They're using a different name.