

Okay, let’s skip the formal logic talk then and go straight to linguistics.
The question “Good to merge?” does not contain a grammatical error. It is perfectly well-formed by the grammar that native English speakers actually follow in everyday communication. A grammar that fails to parse “Good to merge?” in context cannot parse native English speakers’ actual output.
Schoolbook English is not native English, because it’s not how native English speakers actually speak. Schoolbook English contains rules that directly contradict native English speakers’ everyday usage.
(Standard examples include the rule against split infinitives and the rule against ending a sentence with a preposition. These are not grammatical rules of English as it is spoken by native speakers. To boldly assert them is silliness up with which I will not put.)
Baltimore is south of the Mason-Dixon line. Mason and Dixon surveyed the border between Pennsylvania, Maryland, and Delaware.
In the mid-19th century, Maryland was a slave state but did not secede and join the Confederacy. Enslaved Marylanders were, thus, not freed by the Emancipation Proclamation in 1863, since that only targeted seceding states under Union Army occupation. Slavery in Maryland ended in 1864 with the adoption of a new state constitution.