Yes, in those extreme and unlikely examples it seems strange.
But in the much more likely scenario that US is allowed to attack Japan’s home territories without fear of repercussion, the rule makes a lot of sense.
The rule prevents a lot more abuse than anything else.Actually it’s also historical -
US bombers that had to emergency land in siberian territory were actually confiscated by the Russians. They were neutral in the conflict between Japan and US, and so couldn’t just give back the equipment.
From your own link:
When a power is not at war with anyone, it is neutral. Powers that begin the game neutral, such as the United States and the Soviet Union, aren’t initially part of the Allies or the Axis. The Axis powers are on the opposite side of these neutral powers, but they are not yet considered enemies. While a power remains neutral, it operates under even tighter restrictions. A neutral power can’t move land or air units into neutral territories. It can’t move units into territories or onto ships belonging to another power or use another power’s naval bases, nor can another power move land or air units into its territories or onto its ships or use its naval bases.
However, this is not the case and as Russia is indeed at war across both theatres. So, I get why Russia is prohibited in the Pacific theatre, but the allies should be able to take advantage of their Allies landing territories. Thus, I would like better clarification.