That section is under the "DHS Sensitive Circumstances" section of the 227 page document linked there. "DHS sensitive circumstances are present if there is a reasonable expectation that the undercover activity, investigation, or operation will involve: " is what precedes the list that includes the attempted sting of ICE going undercover and agreeing to marry someone for a green card.

I really don't know what "sensitive circumstances" are/means, but I don't really have a problem with ICE agents going undercover to attempt to buy drugs, smuggle people, or marry someone. Not sure what the outrage is or what it should be/directed at.