You can simplify that sentence and make it "Anything regarding your children involve a little bit of effort on the parents part." Yes, that's the true, folks, having kids is hard work, for the rest of your life.
More on the topic, my own 8 yo daughter never payed much attention to PC games (she loves to play on the iPad), but when she saw me playing Minecraft, she got interested. She likes to watch, and sometimes play a bit, she is still getting the hang of the keyboard+mouse controls.
Part of the appeal is the feeling of having a "sandbox world" where you can build almost everything, and let your imagination run free. Discovering the several combinations between items and the "rules" of the world is also very rewarding.
The whole retro look is spot on, and it might be part of the appeal to kids, with its simplified blocks, colours and sounds (my daughter loves the bunnies, curiously there is no merchandise with the minecraft bunnies). Also, she doesn't like it when I kill any of the peaceful mobs (pigs, cows, sheep, etc) and she's grown fond of the Enderman for some reason. The music is also great, and to my big surprise, she commented on it before I did.
Also, the fact that Minecraft it's conceptually the equivalent of a Lego kit (where you have a bunch of "resources" and some loose rules, and you run with it, building whatever you imagine), might also contribute to the appeal of Minecraft, to both kids and grown-ups.