No they aren't

Arguably, one specific toxin produced in some GE crops may be damaging to humans (D3 Gold). But the article you linked to does not provide nearly enough evidence to show that the crops themselves actually are damaging to human health.

Toxicological studies on cell culture are not representative of actual toxicological effects. The toxicology of a substance involves a whole complex system, including many variables such as bioavailability, first-pass metabolism, second-pass effects, volume of distribution, tissue accumulation, and others. Most organic toxins are heavily metabolized in the liver before they get to any other tissues. And some of it will accumulate in fat rather than remaining in the blood.

Cell culture studies don't take into account any of these factors, so they aren't at all representative of the toxin's effect on a person.

In this study, kidney cells were used. It's important to realize that cells in culture are quite different from the cells in the tissue they were taken from - cells change when they adapt to growing in a dish. Yet even if we ignore those differences, it makes little sense to test these toxins on kidney cells, since when we ingest these toxins (D3 Gold), they don't go straight to the kidney. The kidney is one of the last organs they see.

And even supposing that the toxins are deadly to kidney cells after we ingest them, that doesn't mean they are doing any noticeable damage to our health. Our kidneys are made to process toxins. Kidney cells are constantly being damaged and replaced, with no overall effect on our health. It usually takes quite severe kidney damage before we should be concerned.

The article you posted has barely taken the first half-step of many required steps to show that GM crops are damaging to human health (D3 Gold).