In metaphysics, one of the three major branches of philosophy (the other two being epistemology and axiology), there is a concept known as identity. Identity in metaphysics is not the same as the commonly understood concept of identity. Identity is rather about what makes something itself. Is the me of today the same person as the me of two decades from now, even though I would've, of course, changed in some fairly major ways between then and now. It seems like there would be an obvious answer (same body, including brain, means same person), but what if you took me and put me in a computer, would I still be me then? As you can see it can be very complicated. That being said it's worth investigating as often these theoretical matters can have practical effects. Case in point: when an alliance is criticized for acts many years in the past, can one genuinely say that the alliance that did those things is (fundamentally) the same alliance that they are criticizing now?
The short answer to that question is yes, it is the same alliance. The long answer is more involved. First off, it's important to recognize that alliances to evolve over time, meaning they do gradually change. However, there is a big difference between gradual change and drastic, sudden change; the latter occurring lends much more credence to the hypothesis that some alliance is in fact fundamentally different than it was in the past. Alliances are more than the sum of their current members, they are an amalgamation of all members' (past, present and future) contributions to the alliance and its culture, traditions, customs, and even laws. Members come and go, but there is virtually never a case in which all the members of an alliance leave at once, and then new members join having had no interaction with the previous members. In such a scenario, hypothetical though it is, it is clear that the alliance as it existed prior to the mass exodus is no more, having been replaced with something new. It has no links to the past and thus cannot genuinely be said to be fundamentally the same alliance. In virtually all cases though alliances that have aged are not fundamentally different at point A in time (the past) than at point B in time (now or in the future).
Of course, actual disbandment with later reformation can also result in different alliances, with the new alliance being fundamentally different from the old one. However, this is not really important for the sake of this argument because the vast majority of the time, criticism of the sort discussed above is directed at alliances that have never disbanded and reformed, they've just been around for some time.
It might seem as though this whole endeavor is just a bunch of theoretical nonsense, but it is actually really important because if the alliance one is criticizing in the present is not the same alliance that did those past things for which one is criticizing it, then the criticism is entirely misdirected and thus invalid. It would be like criticizing someone for a murder committed by someone else that just so happens to have a similar name; if they didn't do the crime, they don't deserve the criticism for said crime, and it really makes no sense to level such criticism towards them.
But, just for the sake of argument, let's suppose that alliances that have merely aged are fundamentally different than they were in the past, that even without sudden changes an alliance can become something entirely new. The issue then becomes where do we draw the line? How much time and gradual change does it take for an alliance to become something new? Is a few years needs, a few months, a few weeks, or even a few moments? Going down this road is inconsistent with the way CN operates and has operated. If the line cannot be drawn precisely (or even close to precisely) then it becomes impossible to know if the alliance one is dealing with at one moment is fundamentally the same as the alliance one was dealing with in the previous moment. How can one negotiate, war, make peace, or even deal with in any way another alliance under these conditions? It doesn't seem likely that one can, but this happens all the time in CN, which means this theory of the world is inconsistent with that world.
That all being said, is it actually a good idea to level these types of criticisms given it is at least possible to do so? Probably not. Arguments need to be persuasive for them to work, and it isn't persuasive to justify either your dislike for an alliance or your case for others to dislike them as well by bringing up a few acts that were committed by that alliance well in the past. Firstly, if these acts are well in the past, it only means that the alliance was acting badly then, not now, and it makes no sense to dislike an alliance now if it's actually acting well now. Granted, it could be acting poorly now too, but then your argument is still not all that persuasive because it doesn't mention anything recent enough to establish that. For an argument of this sort to be persuasive, it has to establish a pattern of poor behavior on the part of the alliance in question. It has to demonstrate that the alliance has acted poorly over time and consistently through time. This doesn't mean that it has to demonstrate a pattern of bad behavior stretching all the way back to the alliance's founding (though that obviously couldn't hurt), but it has to establish more than just poor behavior at a few points in time that are long since past.
It is possible to make a less-than-persuasive argument, but it isn't a good idea to do so as it is ultimately pointless. Anyone who you might want to convince is likely going to see right through your argument to its empty core.