I hear you on the psi and clinchers, and the pump accuracy. I'll check the reported psi against some other pumps. But I really hope 35 psi is realistic for 33c clinchers.
3 of the flats were punctures so I do think these specific tires are designed entirely for weight and not at all for durability. (We don't have goat heads, whatever those are, punctures here are usually from sharp rocks or man-made sharp things.)
Also, I know everyone's experiences are subjective, but I run 29x2.* tires (much larger obviously so who knows if the comparison is meaningful at all) at 18-20 psi, which I know is super low, but I have never once pinch flatted. I've punctured, gashed, and destroyed 29er tires in all sorts of ways, but never pinch flatted. Also FWIW, that 18-20 psi is using the same pump.
Of course, if I continue to flat every 30-40 miles with new tires, it will become much harder to blame the tire.