My fellow boaters, please take a minute to step back from the keyboard. I do not want this to turn into a private battle between a couple of our members. I will ask for a cease fire and the next post that is directed at an individual will be deleted.
Please keep to the topic, and only the topic, at hand.
Now, back to OP... the regulation you linked tells me the mooring belongs to no one. Therefore, if you move it or remove it will bring no recourse back to you as there are no rights assigned to that mooring. It will cause some bad blood (if not already) between you and your neighbors. Next time he (or they) place the mooring there, make a video and make sure you can see their faces. If the mooring breaks free and damages your dock, you have proof it was they and they should be liable. But you must have proof, tangible evidence.
I read it exactly the same way. The MD laws concerning moorings are very loose and intended to prevent only interference with obstruction to navigation and riparian rights, giving no one actual ownership or control of the water between the two.
In order for the OP to have any realistic settlement they will have to recognize as well as negotiate with the other parties respecting their rights to access also, but I believe that anyone else would be able to do the same thing and place a mooring or anchor there.
If we take the alleged disrespecting young adult out of the equation, therefore the emotional aspect, is the true objection that someone is placing a mooring there. Is the crux of the matter no matter who placed the mooring you would object?
I believe you have the right to protect your property from damage and this is good advice how to do that.
Dave