This is only one bombing of many.
Other stories have come out over the past several months of bombings at government buildings as well as the assassinations of judges and other government officials. You report with glee any bombs that go off in Iraq, but seem saddened by any that go off in Iran. Maybe you should be the one getting a grip. It's time we let Iran know that they're not the only ones that can create mischief.
BTW, notice where it went off. It went off in an Arab majority region that wants to be independent of Iran. So much for Iran carving out a Greater Persia out of southern Iraq.