Scare tactics advertising
It certainly is a different marketing tactic than the fun and easy approach employed here in the U.S. Different approaches used to address the likely mutual public perception in both countries that diving is dangerous. Is there a large number of uncertified divers in Brazil? This is not the best tactic to attract people to dive training courses, although it may work to some extent to attract non-certified practicing divers. The question is: What keeps them away? Cost? On the other hand, the easy and fun tactic attracts too many who quickly drop out.
These are probably extremes of marketing tactics. One keeps too many away, including many who could safely practice it and enjoy it, the other, attracts too many, including many who can't safely practice it and enjoy. A large drop out rate probably makes the last one feasible.