Are we back to this? You say, "All things being equal, everyone would prefer an outcome that is pareto superior." But that's a theological rather than a philosophical statement. What you mean is that in a perfect world in which no one deserves to be harmed, the optimal economic outcome would be one in which no one could be further advantaged without harming someone else by taking the latter person's stuff.

But in the real world, lots of people don't deserve what they've got, and that concept of desert is philosophical (moral, or possibly religious) rather than economic. When you say, then, that economists take pareto optimality for granted as a self-evident principle, to me you're conceding that economists presuppose a laissez-faire ideology. That ideology says we should take the utopia, in which everyone tends to deserve what they've got, to be relevant to distributing resources in the real world in which there's no such tendency (because of luck, subcriminal villainy, broken legal and political systems, natural inequalities, and so on).

And by the way, the language of pareto efficiency is far from being an upfront way of talking. On the contrary, it's very roundabout, casuistic idea.