Most of us have had jobs where we don't follow the rules to the letter. Sometimes they just don't work very well, or we cut corners because we're short on time. However, there are plenty of regulations in place that are there for good reason, and it's a stupid idea to ignore them. Thousands of people die from fatal work injuries every year, and it can be pretty simple to avoid adding to that number.
Unfortunately, there are many out there who choose to disregard this. It's not every day that they get pulled up on it, either. As a result, it's probably a good thing that u/AQuietBorderline happened upon a coworker being irresponsible with some dangerous machinery. When she was patronized for getting angry about him jeopardizing his safety, management got involved — and things didn't go the way he expected. Still, it was better than becoming part of a grim statistic.