Nearly 20 years ago, I asked for nitrox 32 while diving in Cozumel, and the dive operator would only let me use it for one dive. The other dive had to be on air. That was pretty standard procedure when nitrox first stated to get used there. The DM would not let me use it on the first dive, planned to 80 feet. He gave the whole boat a lecture about why it was so dangerous to dive 32% nitrox on a dive planned to 80 feet--you might lose buoyancy control and suddenly plunge more than 30 feet and immediately die a horrible death. I could only use it on the dives planned for a max of 50-60 feet, with a hard sand bottom below us.
A few years later I was diving with a different operator, and they let me use it on both dives. Everyone on the boat was pretty experienced, and they noted that I was the only one allowed to use nitrox on the first dive. They deduced that I must be someone special. (I was an instructor by then, but I didn't think that was so special.)
It is completely different today. I was in Cozumel this past June, and everyone on our boat used 32% for both dives, including the Devil's Throat dive where we were briefly at about 125 feet. No big deal.
Thinking on nitrox has changed dramatically over the years. In the early 1990s, presentations on nitrox were not allowed at the annuual DEMA show--too dangerous even to talk about it. When I was first certified for it, my exam was 50 questions, with lots of math using a number of equations. It was one of the hardest exams I have ever done at any level in scuba. Today the exam is a piece of cake. The hardest part of the old exam was the calculations for pulmonary oxygen toxicity--it isn't even in the course today.
So the the thinking on the dangers of nitrox has changed dramatically, but some people are still deep into old school thinking.