Interesting points. However, this NAICS is specifically for office of lawyers. You cannot be a lawyer without a license. Performing legal services without a license is considered practicing law without a license, and illegal. Secondly, lawyers are not permitted to engage in a business relationship with a non-lawyer where the services offered are legal services. It's an ethics rule to prevent non-lawyers from influencing the legal advice provided to clients. It's grounds for disbarment.
Similarly, there is one for CPA's 541221 and Physicians 621111, however their rules are slightly different, with physicians be more closely aligned with lawyers. CPAs need to own 51%. Engineers/Architects, as well. These are highly specialized licenses.
Here, there are other NAICS codes available for non-lawyer legal services (ie paralegals/stenographers). The contracting officer chose this particular NAICS. Either they intended to have lawyers perform the services, or they chose the wrong NAICS.
Additional thoughts?