Apollo started from scratch
While I agree Mars One has only a small chance of actual success, it's not reasonable to compare their challenges to Apollo. Apollo had a totally different set of challenges.
Apollo (and it predecessors) started with only minimal rocket and no manned space-flight technology, and basically had to invent *everything* - how to get to space, how to orbit, how to dock and undock, how to land on another world and lift off to orbit again, how to avoid fatal doses of solar radiation - *everything*.
Mars One, on the other hand, is getting most of their travel technology off the shelf. The Orion spacecraft, built by Lockheed Martin under a NASA contract, will be capable of delivering humans to Mars. America has landed numerous rovers on Mars using several different techniques, and kept them operational for years at a time. We've built several space stations, including the international Freedom, on which people have survived in space for almost a year at a time. We have a broad range of standard space tech and techniques on which to build.
Mars One's challenges are unique and interesting, but small enough to give a fair chance of non-trivial success. They will need to invent robotic construction techniques to build the colony and manage agriculture until the colonists arrive, and design and build the lander that will travel with Orion and get the colonists to the surface. No idea if they can pull that off for $6 billion, but if they can tap the benefits of free culture as open source software has done, it's quite possible.
How long the colonists can survive is the big question, and the point of the fatwa. If a key piece of tech breaks before the colony is able to begin building its own indigenous housing and agriculture tech, they have no plan B. Develop local tech or die.
But a lot of people are willing to risk their lives to make the attempt, and I applaud that spirit.