Meaningless in substance if not in form.
Maryland was occupied by Federal troops - Lincoln had suspended habeus corpus and was arresting any suspected southern sympathizers- holding them at Ft. McHenry - 2000 by the end of the war.
Baltimore had the largest population of free blacks in the country.
Baltimore was a major transport hub - essential to the Union war effort.
Two or three major railroads went through Baltimore- essentially the only way to get troops to DC from the north.
Baltimore was key for controlling the Chesapeake after the Union lost their naval base at Norfolk in 1861.
So I say the vote was meaningless because if Maryland had voted to secede- they would have been powerless to do so.
Also - Frederick is 45 miles from Baltimore - not far off even in those days.
Not joining the rebellion was the desire of the Maryland legislature so how was that meaningless?
Maryland was occupied by Federal troops - Lincoln had suspended habeus corpus and was arresting any suspected southern sympathizers- holding them at Ft. McHenry - 2000 by the end of the war.>
Hyperbole and exaggeration aside, the Constitution gives the president the power to call out the militia to suppress rebellion. Lincoln was acting well within his authority.
So I say the vote was meaningless because if Maryland had voted to secede- they would have been powerless to do so.
If Maryland had joined the rebellion then I expect they would suffer the same fate as the other rebellious states - armed conflict would have come to them and all the death and destruction that followed would be their own fault. Good thing for them they remained with the Union.