Apart from the non-organic portion of liquids, doesn't just about everything you consumer consist of organic cells filled with DNA? Plants, animals, it's all DNA
The parent said it was caused by consuming DNA. All DNA is broken down during digestion.
That is not a useful generalization if it's actually a small sliver of broken down DNA that causes the issue. It's like saying "all food-borne illness is caused by eating DNA." It may be literally correct, but is general to the point of adding no value in understanding the specific cause of the problem.