It doesn't matter what they are a part of...a screwed joint on the pipe itself is not any different from a srewed connection to a metallic faucet body. If you are saying that the metallic faucet body and its joints are not suitable for bonding(YES), then you also have to say that the pipe joints themselves are not suitable for bonding (No I do not.). You can't have it both ways.
Also since solder is not permitted as a connection method for bonding or grounding conductors, how do you permit a single point of bonding to a copper water pipe system installed with sweated joints?
The NEC calls the pipe and the fittings a system
.(" (1) General. Metal water piping system(s)") Fittings and solder are part of the piping system, not 'bonding conductors'. If fittings were NOT part then all systems would be limited to either 10' or 20' (standard length of pipe).
Fixtures are supplied by the system.
PLUMBING FIXTURE. A receptacle or device that is either permanently or temporarily
connected to the water distribution system of the premises and demands a supply of water therefrom; discharges wastewater, liquid-borne waste materials or sewage either directly or indirectly to the drainage system of the premises; or requires both a water supply connection and a discharge to the drainage system of the premises.
604.3
Water distribution system design criteria.
The water distribution system shall be designed, and pipe sizes shall be selected such that under conditions of peak demand, the capacities at the fixture supply pipe outlets shall not be less than shown in Table 604.3. The minimum flow rate and flow pressure provided to fixtures and appliances not listed in Table 604.3 shall be in accordance with the manufacturer?s installation instructions.
SECTION 607
HOT WATER SUPPLY SYSTEM
607.1 Where required.
In residential occupancies, hot water shall be supplied to all plumbing fixtures and equipment utilized for bathing, washing, culinary purposes, cleansing, laundry or building maintenance. In nonresidential occupancies, hot water shall be supplied for culinary purposes, cleansing, laundry or building maintenance purposes. In nonresidential occupancies, hot water or tempered water shall be supplied for bathing and washing purposes. Tempered water shall be delivered from public hand-washing facilities. Tempered water shall be supplied through a water temperature limiting device that conforms to ASSE 1070 and shall limit the tempered water to a maximum of 110?F (43?C). This provision shall not supersede the requirement for protective shower valves in accordance with Section 424.3.