There had been scattered reports and allegations that this sort of thing was going on. This report will make it impossible to ignore, however.
It reminds me of the widespread torture during the US occupation of Iraq. Using power tools for torture was so common that it was a go-to joke for the War Nerd.
In a more general sense, I think it shows that the constituent groups of Iraq cannot rise above sectarian identity. If there's peace, it's because one group has conquered the others and has ejected them from the political sphere. In Saddam's time, the Sunni Arabs held supremacy (albeit in a secular, ostensibly nationalist state) and suppressed the Shia Arabs and Kurds. Eventually, the more numerous Shia Arabs will probably take control of Iraq, at least outside of Kurdish areas which will probably be de-facto autonomous. A democratic government there with full participation by all groups is doomed to bloody failure.