Your contention appears to be that the loss of 4 Japanese fleet carriers at Midway was somehow unrelated to, or of little importance, with respect to Japan's subsequent inability to capture Port Moresby.
And your contention that the loss of four carriers at Midway made it impossible for the Japanese to capture Port Moresby completely ignores the necessity of the valiant Australian defense of that objective long after the battle of Midway was fought. I have already argued that Port Moresby was not saved by any one battle, that it was necessary to fight and win a series of battles; Coral Sea, Midway, Milne Bay, Kokoda Trail, and Bismarck Sea before the Japanese gave up on capturing southern New Guinea and Port Moresby.
Midway secured the safety of Moresby
Then perhaps you can explain why the Australians were forced to fight so desperately to hold vital positions at Milne Bay and on the Kokoda Trail months after the Battle of Midway was won by the US? Frankly, I think your statement seriously demeans the sacrifices the Australians made in defense of their own territory and reinforces the myth raised by MacArthur that it was his leadership and the fighting ability of Americans which stopped the Japanese. Coral Sea aborted the sea-borne invasion of Port Moresby and bought time to bolster it's defenses and air power in the theater. That one fact is enough to justify the label of strategic victory for Coral Sea. Midway precluded another Japanese sea-borne invasion supported by sea-based air power, but it certainly did not remove the land-based threat to Port Moresby and, as it turned out, the Japanese land-based forces came within a hair of capturing Port Moresby after Midway.
Frankly, I think the balance of evidence is that Coral Sea was about a draw. Japan won the battle at the tactical level, there is no evidence that 5th Carrier would have been a more important factor at Midway than the Lexington, and stopping the first invasion was indeed worth a great deal to the Allies - perhaps as much as a fleet carrier. But only because the USN did indeed win at Midway. Had they lost there, then Moresby would have fallen.
Your arguments all rely on speculation; speculation about the effects a changed OOB would have had on the outcome of the Midway battle, speculation on what the Japanese would have done had they won at Midway, speculation on Allied counter-moves contingent on alternative results in the battles actually fought.
The historical facts do not support your contentions. Port Moresby was far from "secure" after Midway, and there remained hard fighting, the results of which were by no means fore ordained, before Port Moresby could be considered safe from the Japanese. As I said before, it was necessary to fight and win a string of battles, at sea, on land, and in the air, before Port Moresby could be considered safe. This is not "blurring" the effects of these battles as they were all interrelated to one degree or another and looking at them simply within their own context is an oversimplification when trying to understand the history of the Pacific war.
