In his community (which handles power tools much more frequently than I do), it’s a combination joke and reminder. Everyone says “Safety First”, but this is a lie. If Safety really was First, they wouldn’t be using power tools at all. Power tools improve efficiency tremendously, but at the price of safety – it’s impossible to accidentally cut your own hand off with a traditional hand-saw. So things like time and money savings trump safety, and everyone knows it. That’s the “joke” part of it.
But more importantly is the “reminder” part. It reminds you that the Corporate Dragons may say “Safety First”, but they don’t mean it. YOUR safety is not THEIR highest priority. So it has to be YOUR OWN priority. You cannot trust them to act in your best interest in anything, ever. You must personally weigh when the costs outweigh the benefits, and act accordingly. Never trust a them to have your best interests at heart.
Remember, Safety Third.