I think it’s a signal they are going to be targeting officers.
If the stated intent - to spread confusion and disarray - is true, why limit it to just mil officers? Taking out a mayor of a major US city would certainly do that, as would the same to a governor, Senator, or Representative - all of whom have nowhere near the level of force protection as the hapless Iranians.
Between CAIR and the MB operatives in and around the US government, potential ISIS moles are very likely - that is how they get the info to conduct the operations, if you read the article.