My understanding has been that an additional reason breeder reactors have been discouraged is due to nuclear proliferation fears; the neccessary reprocessing of the fuel also produces weapons-grade plutonium.
proliferation argument doesn't hold considering you can do it much cheaper with distributed enrichment of uranium. Breeders can open a pathway for plutonium warheads but it's more about optimization. If a country wants such warheads, it'll start with easy enrichment path