I think utilitarians also have the issue of having ex ante knowledge of another's utility, which is problematic for a utilitarian position, even if it could be quantified and measured. For instance, how could you know what someone's reaction to an action would be before you make it, whether it would increase or decrease utility? In some cases, it may be easy to deduce, but certainly not all. We've all been in situations (or at the very least could imagine them) where we think we're helping, i.e. increasing utility, when in fact we're doing the exact opposite, which is immoral to a utilitarian. Rule utilitarians try to get around this through proposing generalized rules, but this can be reduced to act utilitarianism and its problems. Moreover, it seems that utilitarianism is open to reductio ad absurdum objections whereby one would be committed to doing something morally objectionable in order to increase total utility.

Hoppe's argument makes no appeal to utility of any sort, which I take as a strength. He is very Kantian in his approach invoking the principle of universalizability and acknowledging that sometimes things might not work out, but we have, on his view, these inviolable principles to abide by.