A utilitarian would absolutely say that causing one group severely negative utility is worth a corresponding positive utility in another group. However, they'd

A utilitarian would absolutely say that causing one group severely negative utility is worth a corresponding positive utility in another group. However, they'd also say that these are useless examples to apply knee-jerk aesthetic analysis to, because they're practically impossible. The aversions we have to this kind of inhumane utility juggling are because we instinctually recongize the second order and knock-on effects without needing to specify them. Dehumanization, inequality, precedence - these are all utility-real things which a responsible utilitarian incorporates into their utility calculus as major negative impactors. When you strip the situation of any practical relevance, of course the conclusions are 'stupid' because the criteria you apply to determine that stupidity are based on a practical reality.