Actually, real scientists use their knowledge to develop new drugs, vaccines, medical devices, and treatment protocols. An engineer is not going to create a library of chemical compounds to screen as potential drugs against pesticide poisoning, but an organic chemist--a scientist--routinely does such work.
Most new products developed through the scientific method require people from a range of disciplines.
The author of this piece is wrong. I doubt there are many engineers working behind the scenes to analyze courses of action, efficacy of control measures, etc. That's the work of scientists and mathematicians.
You are correct. Engineering also uses the scientific method and many different disciplines. The original statement would be more correct if it said theoretical scientists. Most of the models are coming from universities where the people building the models are not engineering any product other than social change. May I add, a lot of the people building those models are cross-discipline people that have little rigor to their disciplines.