We could go further and say that the N type, in loving himself, feels harmed or besmirched by holding grudges. We might also say that begrudging another person offends his idea of goodness, whereby others must be treated kindly and goodnaturedly; the classic inverted narcissism. We mustn't forget that the N type's strong preference for smooth, simple and cordial relations erodes, day by day, his ability to begrudge. If he is charismatic or charming, then reconciliation may become a skill of his.
It's worth noting that any type, including the N type, with a high temperament tends to find it harder to drop a grudge or 'let it go'. Those with either A or P trait are likelier to hold grudges long term. Those with perfectionism hold grudges against person/s felt to have transgressed their sense of order. For some perfectionists, grudges are not merely a preface to revenge, but can be a way of life - the parent or teacher begrudging a child for failing to meet behavioral or academic expectations, or the employer begrudging his employees for taking their mandated breaks, are examples. Perfectionist grudges can be irrational; a projected sense of self-aggrandizement and berating.
Sometimes perfectionist grudges can be an extension of his demands upon himself and others; a sort of ever-present mild disappointment or pessimism in humanity, externalized upon many in his social circle. More severely however, the perfectionist grudge can permanently alienate others or render him misanthropic or overtly standoffish even to newcomers. Most commonly the PA type, but also haughtier and tetchier NP types, can be saddled - they might say 'enlightened' - by grudging tendencies.
The A trait grudge is based around the need for power, down to and including sole individuals. Defiance or thwarting of said power and dominance can result in grudges. Sexual jealousy and the associated grudges can be further fueled by the A trait, although such are certainly not exclusive to those with A trait - yet the emotional charge of dominance and submission does much to potentiate enmity. Occasionally, grudges can erupt into violent revenge or cycles therein; Shakespearian and other literary lore, as well as many historic generational family feuds, spring to mind. Those with the A trait can come to view grudges and revenge as part and parcel of existence, perhaps even a justifiable or moral approach to life - "An eye for an eye, a tooth for a tooth".
All this is of course general. In the modern era, we are all restrained from violence by civilization. Methods such as dueling, whereby a grudge is solved with stark violence, are alien to our present culture. There are plenty of unbridled N types who, especially in pre-modern eras, would readily hold long grudges especially if it entailed honor, personal prestige or peer pressure. There are many P trait holders whose idea of perfectionist harmony is affronted by grudging; quieter, more solitary perfectionists simply reduce their overall contact to a select few. Nowadays, A trait personages restrain themselves from acting violently on grudges, or behave covertly or passive-aggressively to settle scores.