Where are you getting your information? In the US, the CDC and the mass media is reporting that it's primarily the black market ones causing the problems. Additionally, about 11% of the cases do not even involve cannabis products.

To wit:

The latest national and state findings suggest products containing THC, particularly those obtained off the street or from other informal sources (e.g. friends, family members, illicit dealers), are linked to most of the cases and play a major role in the outbreak.

https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html#what-we-know

If you have a contrary information or evidence, I'd be interested.