Looking at it from the other side, I would hope that if a Chinese military plane came close the shores of Hawaii/Alaska/Pacific Coast we would be just as aggressive. To me the "diplomatic" route should be when we are the visiting team.
Oh we do. During the Cold War it was very common to have a Soviet "Bear" bomber come over from Siberia into the Bering Sea and we would scramble interceptors to meet them before they entered US airspace. This behavior declined as the Soviets migrated into today's Russia. The Russian Air Force has recently started up the "penetration" flights once again and make the trek to the Bering Sea to test our response times.
However a key difference between those flights and these done by the US forces is that our flight path is not into territorial airspace. We stay out over international airspace and run parallel. So we don't present ourselves as if we are attempting to make an overflight. (We haven't attempted a military overflight of Communist China since the early Sixties).
And the last time a set of Russian "Bear" bombers flew to Venezuela, it was over international airspace and we did not shadow them or bother them in the least. In fact US was criticized for NOT shadowing them. Our response was that they posed no threat to us as they remained in non-US airspace and therefore was really none of our business.
Now if a Russian AF sent a recon flight along the Alaskan coast and stayed in international airspace, I am sure they would be shadowed, however I don't think USAF would be doing barrel rolls over the top and cutting them off in the air and make it unsafe. But just like the PLAAF, we would let them know they were in our backyard.
I think that is the distinction DoD was making in the press conference. "You have a right to shadow, you have the right to share the airspace...you do not have the right to endanger us and act unprofessionally"
