I see the argument. And I can't say I disagree with this being a 3A violation. But I don't see any judge wanting to be the one that opens this door. Though we do need it thrown open after what happened in Boston.
When the 3A was written, the troops did the law enforcement. Bandits and brigands on the road were chased down by the militia. This is one of the very reasons we now have Posse Comitatus.
Additionally, we have pretty much the only case law on the subject in 724 F.2d 28: Marianne E. Engblom and Charles E. Palmer, Plaintiffs-appellants, v. Hugh L. Carey, Governor of the State of New York, et al.,defendants-appellees
United States Court of Appeals, Second Circuit. - 724 F.2d 28
Argued Dec. 15, 1983.Decided Dec. 20, 1983
In that case during a corrections officer strike, New York mobilized their National Guard, and evicted striking corrections officers from government housing to make room for the National Guardsmen who were going to perform the correctional duties.
As a result, in this district- and persuasively to the rest- the Third Amendment has been incorporated against the states, and National Guardsmen performing a law enforcement task were considered soldiers.
National Guardsmen under State Authority can and without looking into it too far from state to state do have arrest powers. Georgia § 38-2-307 - Power of National Guard members to effect an arrest
Given the early history of militia and troops in the Whiskey Rebellion, and various other early law enforcement tasks, the Posse Comitatus act trying to separate law enforcement, and military, the hybrid nature of the National Guard today and their still being "soldiers" in a state law enforcement capacity it's not that much of a logical stretch to compare a bunch of armed agents of the state in BDU's led by a sergeant as "soldiers".