Whatever you say. No sense in arguing with someone who has read the history and still does not believe it.
Certainly the Calvert colors and the Botany Cross are rooted in colonial history, but the two were not put together to form the present day flag until after the Civil war.
Sorry; you said it had “roots” in the CW. I see “roots” as its background, not the flag itself.
Plus, in that same history, you’ll see they incorporated the Calvert/Crossland combo in the state seal just prior to the CW - never mind Calvert used both his families’ colors exactly that manner when he came here. So, such a combo was not brand new to anyone with some knowledge of their colony/state back then, apparently including 1854.