He said Europe should pay their fair share for protection since 40% of their trade passes through those lanes but only 3% of America's.
To be clear, im not saying protecting shipping is the primary reason for this war. I'm just saying if that is what you think usa should be doing, then this war makes sense.
As far as b) there are a lot of factors. Its not like freedom of navigation is the top concern of every country in the world.