Yes, it probably is a bit dubious, but it's also not really what happens in Dune. The Fremen, unarguably, are hard people (women as well as men) from a hard place, but Paul, who ends up leading them, comes originally from a fairly hospitable and civilized planet, I think. And the Imperium may be 'corrupt', for a given value of corrupt - OK, the Emperor breaks galactic law by secretly siding with one House against another in order to destroy a perceived threat, which is pretty corrupt - but the Emperor's own army is anything but effeminate, and is universally regarded as invincible until it comes up against the Fremen.