Yes, that is a very good article. Ironically Kirby (CANNON-MAN) and I were just talking about this very subject yesterday. I did a fairly detailed write-up about a year and a half ago on this subject.
Curing Sausage with Celery Juice - the experiment I spent almost a year (off & on) researching this and let me tell you, good info was NOT easy to come by. Much of it is kept secret withing the food trade because they don't want you knowing.
They are counting on people like your friend NOT reading the label carefully. Nowhere does it say "Nitrate/Nitrite Free" or "No Nitritates/Nitrites."
What the label says is "No Nitrates/Nitrites
ADDED," meaning that no Sodium Nitrate or Nitrite was added as a
separate ingredient.
The two most common sources of "natural nitrates" being used are Celery Juice & Cherry Juice. In addition, some are also using Sea Salt (which also contains nitrates.
Most folks do not realize the biggest source of nitrate intake is from veggies NOT cured meats.