It's not pozzed. It's just default. Not any more radically Leftist than Star Trek (ENT and before).

There's a lot of silly things in this, that kind of speak to why people view "nationalism" as evil, when the presenter is effectively siding with that evil.

Saving an interstellar government that would otherwise cause the fracturing of the entire galactic order isn't an unreasonable and irrational choice because humans may die. Especially because there's a possibility that humans could be explicitly blamed for their deaths, which goes into how the presenter doesn't seem to understand that "Shepard didn't order their deaths", just after playing dialogue which explicitly states that Shepard intentionally held support in order to kill them. What his Renagade Shepard did was not only a coup, but an assassination. Just because you don't pull the trigger, it doesn't mean you weren't conspiring to commit murder.

What the presenter is effectively saying is that the intentional assassination of uncooperative government bodies is never illegitimate, so long as someone else can be blamed for the immediate act, and since it's for the alleged benefit of your faction, such conduct is necessary.

This is one of those reasons why I say: "The jews did nothing wrong." No ethno-nat can tell me that the jews did anything wrong, even by their own logic of subverting every nation, corrupting every system, and working to keep the world off-balance and at each other's throat for their own benefit. You'd do exactly the same thing given the chance. Jews aren't actually doing this, but this is confession through projection on your part. There is no reason you wouldn't do the same, including subversion, degeneracy, assassination, and genocide so that you may gain some tactical geo-political advantage. It's not that you're mad about anything you think the jews are doing, you're just mad that you think you are losing.

It seems that the purpose of Mass Effect 2 is to teach us something about how you can't trust Nationalists because they will invariably seek Imperialism and confuse personal ambition with public interest.

Well, you can't trust racialists because that sentiment is exactly correct. It is the assertion of the racialist that they are the final arbiter of the race they claim to represent. This is true of all identitarians. It is even more true in regards to totally unaccountable shadow organizations that have no real mandate and no real feedback to why what they do may or may not be wrong. The first person the racialist kills is the perceived race traitor. This is because there is no other greater threat to him than the person who represents an alternative hypothesis, analysis, or any sort of dissent that does not correspond with the person claiming authority over the race. This is always the case, and has been standard Leftist policy since Rousseau alleged the existence of The General Will.

This is, of course, not a problem inherent to Nationalism, but to any form of authoritarian identiarianism. It's just that the easy targets for this are the racialists, because the claim of working for the absolute benefit of the race by being the sole arbiter of it, is such a laughably false premise that it shouldn't be taken seriously. The problem with our modern times is that the Left has made these claims serious but only to certain groups.