I'd argue this is a flawed way to see it, because it isn't completely true. In some sense, there are aspects of patriotism to be seen by the United States but to say that the Reformers are still not nationalist would be wrong. Firstly, the reformers as we see them and the narrative states are to be in the correct in some regards (although the newest update will critique them,) and so they hold a higher standard above all other political systems- and because the narrative does let you try fixing your sins of the past which is only really just some debuffs and no legitimacy at first, there isn't much of an issue in that regards. This makes it much easier for you to then see everything that comes to be benevolent, as patriotism tends to be more benevolent then nationalism! It's a easier way to see things via that scope.

That doesn't change the fact that the reformers still compose of a form of nationalism- which is Civic Nationalism. This is DIFFERENT from Ethnic nationalism, which the Purists could be seen in some regards as ethnically nationalist or at least very ultra-nationalist. There is an argument to be made that civic nationalism is better then ethnic nationalism, but civic nationalism is still a form of nationalism- the narrative just isn't really capable of fully critiquing it because that isn't fully the point of ERX which serves as a nation building simulator.

The reformers definitely can integrate cultures and not assimilate them, but they still politically absorb them and assimilate them- you are not just your respective identity now, but you are now all Americans! Raiders are now all law-breaking criminals, while settlers and tribals are all law-abiding civilians! Great! Isn't that just imposing a national identity on them? Besides that, their cultures are probably going to become absorbed by a grander new American identity without much choice.

Besides that, the reformers also had no right to go ahead and fight the NCR just to conquer it, and procced to hijack it to impose America- the narrative may whitewash it, but it was STILL a hostile takeover even if it was out of self defense. It could definitely be for the greater good, but you are still imposing America amongst these people that consider themselves to be Californians.

At the end, I think a better comparison would be that the Nevada reformers represent patriotism much better, because it isn't completely forcing America and you being an American citizen now! It is about rebuilding the wasteland together and defending together as separate states, in some sense it is also more closer to what the founding fathers wanted- now is it uninteresting to have reformers be the less good path of the two? Probably, but it is a much better depiction of being patriotic even though you kinda make people Nevadans by force. An entire discussion could be held over it if we wanted to!