It depends on whether the prohibition on condoms does indeed increase the spread of HIV in non-monogamous sex. If it does, then the combined monogamy+no comdoms

It depends on whether the prohibition on condoms does indeed increase the spread of HIV in non-monogamous sex. If it does, then the combined monogamy+no comdoms policy causes more HIV infections than a simple monogamy policy. Therefore the no condoms policy is a cause of spreading HIV. This would be equivalent to the suffering caused by vegetarians demanding that animals farmed for food should be made to suffer. They can be praised for their vegetarianism, but should still be held accountable for the suffering they cause.