The name of the center should give a clue as to their perceptual bias, but they make some good points, albeit missing a key one with regard to using V&PM Grade Naphtha. Naptha is a mixture of different boiling point compounds falling withing a specific boiling range, and that range includes benzene, a known carcinogen. Early on Rick and I debated that point on a radio show.
I also critiqued the high levels of residual solvent using the rice cooker purge method, to which he noted that they tie up the liver processing them, so as to leave the cannabinoids in our system longer. We thought that was a good point, without saluting it, so started adding coconut oil to our fully purged concentrates to achieve that same end.
What we owe Rick Simpson credit and respect for, was not the process, but his proving that phytocannabinoids can jump start our bodies endocannabinoid systems, which controls our immune system, and restore apoptosis, causing the tumor to commit suicide. It really doesn't cure the cancer, our own immune system does, just as it was designed to do, when functioning properly.
He was of course persecuted for those views and fled prosecution at one point.
As to the rest of the article, concentrate extracted with ethanol using the QWET process, will contain the cannabinoids that you covet, and not be pernicious if you don't get it all out. If you extract below -18C/0F, and control your soak time, you can avoid picking up undesirable non targeted elements like chlorophyll and plant waxes.