"Johnson & Johnson has registered the symbol for their medicinal products."
How did this ever get approved?
"The appropriation of the symbol has led to further irritation due to the practice of hospitals, first aid teams, and ski patrols in the United States reversing the symbol to a white cross on a red background – so undoing the original idea of the Red Cross emblem, namely reversing the Swiss flag – thus inappropriately suggesting an affiliation with Switzerland."
The wiki article says that J&J was using the symbol before the US started enforcing protections on it. So the answer to why it was approved is that there was no law preventing it from being approved.