Similar or not, a lot of very highly-paid lawyers would love to argue over this for weeks.

My general argument is this whole situation is not as clear-cut and black-and-white as the developer in question asserts, however ‘moral’ or justified his objection to second developer’s seemingly less defensible actions in copying his work.

There seems little ‘right’ or ‘wrong’ here, just very subtle shades of grey and legal interpretation of who owns which rights to various elements of data, code, design and structure.