How many Marylanders joined the Confederate Army and fought against the Union?
More than a few I guess, but only about a third of the number who fought for the Union.
The fact that that a relatively small number of people appropriated a symbol from the Maryland flag does not make the Maryland flag Confederate. Far more Marylanders supported the Union, so the Maryland flag would be more accurately viewed as being anti-Confederate, just as the flag of New York or Pennsylvania.
Whether you view people who would leave their homes to support the Confederacy and slavery as racist idiots is up to you.
I call them that not to besmirch Marylanders in general, and certainly not the Marylanders of today. But to travel south to support the Confederacy and slavery in 1861 you would have to be a racist, and given the futility of the cause, idiot could not be far from the truth.
Virtue signaling is your forte i see
And facile logic
Keep going