Should your home state be overrun with what amounted to foreign (Other States, and keep in mind the State was a sovereign entity, and those Militias were still State Armies) and Federal troops, what would your reaction be? Lay back and try to enjoy it, or resist?
Well, every state I’ve ever lived in had federal military installations, as indeed did Maryland, long before the war. You may have heard of the Star Spangled Banner, written about the defense of Ft. McHenry against the British.
As far as the revolutionary authorities bit goes, there are only two choices.
Either the MD state government and Baltimore city government were waging war on the United States in their official capacity, before they had made even a pretense of secession. In which case it was by any standard treason.
“Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort.”
Or there were extra-legal bodies in control of parts of Maryland, bypassing the state government. I think the army officer in command of Ft. McHenry took the polite approach of assuming private individuals rather than state officials were committing treason.
Marylanders either waged war on the United States, from which they had not seceded. Or they were giving aid and comfort to states that were waging war on them, or possibly to a foreign nation, the CSA, that was at war with the USA.
It must have been hundreds of times I’ve seen Army convoys heading from one post, presumably, to another. You know, it has never once crossed my mind to get some friends together and try to ambush them for the temerity of entering my state.
BTW, the state of Virginia committed constitutional treason by attacking US military and naval forces before they had even formally seceded. Nobody ever seems to want to talk about this.