Bullsh*t.
The article specifically states that it is because of its high-quality that people are dying from it.
They are dying because it is purer than what they are used to. Quality control means standardization. If standard legal heroine were always pure, users would cut it or use a smaller dose; if it were always cut to a certain strength they’d be used to that. The problem with lack of quality control, besides toxins in the whatever is used to cut the drugs, which is not the issue here, is random variation in strength. When it fluctuates up, as in this case, one gets the preponderance of overdose deaths.