To say that GPS is absolutely unnecessary when flying VFR is an over generalisation, probably borne out of a narrow pool of experience.
After nearly 20 years of military flying using DR techniques, at up to 330kts at 250 feet in one role, or 140 kts at 50 feet in another, these days I fly a single pilot corporate helicopter, VFR where possible (but with an IFR transit in case of low cloud).
The aircraft cruises at 155kts, most often from private landing site to private landing site. These landing sites are often a hotel car park or someone's back garden. In poor weather I still have to fly VFR in order to make the destination (or even the pickup) but the job would be far more difficult if we had to go back to the old methods, i.e. non-GPS navigation. I do the job by night, too, btw.
Not too long ago we flew helicopters with a manual throttle. Fuel computers made the pilot input redundant but more modern aircraft can still be flown in manual. The same "hairy chested" mentality perhaps says we should not use the automatic engine controls? Or the autopilot? Switch off TCAS too?
Modern equipment is designed to offload the pilot and to increase his capability. By not using what's provided in the aircraft, we aren't proper pilots.