Dell and base memory config
Very simply, I think that the tech at the shop is bullpooting you. Both IBM and Dell P4 systems use absolutely standard Socket 478 ZIF sockets. The differences among Dells, IBMs, white boxes...
This is NOT the same as a radio. If I get a car without a radio, I can still drive to work.
You've completely ignored GOOD answers from others that don't seem to match your opinion.
Bottom line, if they shipped without memory, then Dell could NOT provide warranty support, as they would have no way of ensuring that the memory you added was not the problem. They often require you to return your configuration to factory shipped prior to warranty service to ensure that you add-ons were not the problem. A perfectly reasonable approach. If you had major electrical problems in your car, and they pointed back to your miswiring your wonderful car stereo you added, then the dealer would charge you for the diagnosis, even if the car was under warranty.
Your entire question is unreasonable to even the most casual computer user.
Tom