Utilitarianism is about virtue signaling. It's about claiming to care about all other beings and experiences with a lack of bias. Obviously it isn't rational, or it wouldn't assume the unexamined values of this culture that there are such things as pain and pleasure apart from pain nerve signals or anesthetics. It's an unexamined value right at the core of utilitarianism that there's such a thing as suffering, which is a concept borrowed from Buddhism and wasn't part of Western culture before that. Suffering merely meant to undergo something or to bear something, including positive things, such as sufferage meaning having the right to vote. Western culture did have the concept of pleasure, but it was all about preferences, something at a mental level, not a physical nerve sensation like pain. What pleases a person meant what a person wants. Utilitarianism flattens everything into these gross misunderstandings of language and experience. So utilitarianism in fact has the opposite effect of the purpose it claims, increasing the perception of suffering in the utilitarian sense, for everyone who believes in it.