We agree. Christ's sacrifice was "sufficient" for all the world, and "efficient" for only the elect, since all men are not forgiven all their sins and thus some men are left in their condemnation.
If God wanted all men to be saved, all men would be saved.
God only reprobates those who reject Him. EVERYONE ELSE is "elected" or "predestined". Men are left in condemnation ONLY because they desire it. God desires all men to be saved - but His will is ALSO that God unites Himself to only those who want to be saved. Recognizing our total dependence upon God is crucial to this salvific work that God enacts upon us.
If God wanted all men to be saved, all men would be saved.
Again, that doesn't answer the question why all men are not saved. It is a meaningless cliche, akin to "If God wanted men to obey the commandments, they would". I have shown you numerous Scriptures to show your theology is wrong. We have even shown you specifics, such as Romans 5. Really, reformed theology pretends to be biblical, while ignoring huge chunks of the very bible it claims to be infallible...
The problem with the reformed theology is that it parallels predestination to reprobation. They are not identical nor are they analogous. Making them so makes God into a monster who creates SPECIFICALLY to destroy, giving the so-called preselected reprobate no possible chance of salvation. This is not a God who desires men to be saved. Thus, the answer to your cliche is woefully contradictory.
Regards