clutch fan vs standard fan

4 guys leaning under hood of a Chevy with a four blade stock fan. One was revving the engine quite high, one blade came off and cut one guys head almost off, he died. I raced 8 years with a fiberglass fan on my Max Wedge turning 6800 rpm, never broke. I’ve had flexible metal, stock metal, clutch type, you name it, since 1967 and NEVER broke a single one. Chrysler made a viscous drive unit to use on the crank so the fan, water pump and alt would reduce pull on engine. That was when you had to run the factory setup in class racing