The falkland/malvinas islands were uninhabited prior to the Spanish, British, and French colonial battles to control them. War and force are the only methods that have ever decided who controls falklands/malvinas, not peaceful indigenous habitation.
I wouldn't hold the referendums in Scotland and Donbass to the same standard. Also I would not consider the idea of secession of donbass and scotland to be similar outcomes. The one in Scotland was a democratic process, while the one in donbass was a sham, happening only after the territory was under the control of Russia. If the Scottish one was successful (if Britain didn't stop it), Scotland would likely remain a democracy in close partnership with Britain (or I guess just England and Wales at that point) and potentially join the EU/NATO. In the case of Donbass, there would not be an independent country but a province taken over by Russia.
About the fishing, the difference between the Chinese and Japanese and Korean illegal fishing is that the Chinese fishing fleets are largely encouraged and directed by the government to fish aggressively and illegally.