It may seem, in your opinion and perhaps the other parcel owners that the judge went too far , but finding that the easement (the private road) was public has to be based on the evidence that was presented and the common law. It is not possible that the court would use the word public to denote the rights of dominant estates that abut the road. It would be based on evidence that the public used that road for at least 20 years and gained a public easement by prescription.
You have yet to answer the question whether or not this road connects two public highways. The fact that it is a meandering two rut road doesn't make much difference.
Do you know if the case was appealed?
I researched the Maryland court decisions and found that when the court finds a private road to be public it is primarily based on prescription.
Here is one such case: Garrett v. Gray, 266 A. 2d 21 - Md: Court of Appeals 1970 It is a 1970 court of appeals case. Sounds a lot like your case.
You should read it. It's a bit long so if you want to get to meat of it, scroll near about mid point.

