It's because everybody is tired of getting sued.
No,this stuff started long ago with the emphasis on safety in high risk jobs. It isn't about getting sued, because if a harness fails or someone gets tangled in their safety equipment, the lawyers line up to feed at the trough. The driving force is insurance costs, although the pretty face put on that is that everyone gets to go home with all the parts they brought to work still attached and functional. Consider, that working on a drilling rig used to be right up there in the top ten most dangerous jobs, and the extensive safety programs pursued since the 1980s have removed that job from the top ten. A LOT fewer guys are getting mangled and killed as a result.
But working on an oil rig, while it certainly has its hazards, is not as inherently dangerous as firefighting (I have done both, and a few others on the top ten list). As a firefighter, while you do what you can to keep from being another person who has to be rescued (counterproductive, that), but you are there to save lives and property, in that order, and to contain, control and extinguish the fire. You are going in harm's way, it's part of the job.
Add in too much regard for your personal safety, and you will compromise your foremost mission.
Consider, too, that the average airport crash truck has tires taller than 3 meters, just getting in the cab might require being tied off with fall protection gear, and that really puts this in perspective. A couple of minutes can seriously affect the fire's progress, and that delay might make a big difference in response time and effectiveness.