Really? I think rocket science is still not easy. Just look at how much nation states are spending on maintaining their liquid and/or solid fuel rocket programs. If they even have one, let alone both.

This book might give some insights into the why https://library.sciencemadness.org/library/books/ignition.pd...

Quote: "All this sounds fairly academic and innocuous, but when it is translated into the problem of handling the stuff, the results are horrendous. It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water —with which it reacts explosively. It can be It has recently been shown that an argon fluoride, probably ArF2, does exist, but it is unstable except at cryogenic temperatures.

[...] kept in some of the ordinary structural metals — steel, copper, aluminum, etc. —because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminum keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes."

Granted this is about a fuel that is AFAIK not used for MANPADs, but the joke about the running shoes could be made about most aspects of rocket propulsion.