Lemme ask you this, does the US doing something bad nullify the wrongdoings of another country/regime?
When they’re in the process or about to cause a humanitarian disaster in said country, yes.
Saddam’s regime was terrible, however sanctions, plus destroying vital infrastructure such as water treatment facilities and power plants during war were infinitely worse. The sanctions on the DPRK that have been going on since 1950 compounded the nightmare of destroying all the infrastructure in the country and the killing of 20% of the population and are still ongoing.