A significant part of the article is a reposting of http://www.phys.ufl.edu/~det/phy2060/heavyboots.html
Edit: Changed wording re how much of article is repost
That is an unfair characterisation, I think. The article does indeed reproduce heavyboots in its 725 words entirety (according to pages's word count for what that one's worth), but tacks a further 930 words afterwards. And these 930 are interesting indeed as they're further explorations of the phenomenon and discussion on its underlying reasons.
The reason for choosing b) would have been that the moon's gravity being weak, the earth's gravity nullified the moon's thus having a floating pen.
The reason for choosing d) would be because Moon's gravity is stronger than Earth's.
This is why I think tests are stupids. If I had chosen b) instead of d) I would have gotten a wrong answer. Even though my thought process would be correct. Just missing the right information (which could have been easily found outside a test environment).
So no, I'm pretty sure your thought process wasn't remotely correct.
If Moon was hanging on a stick connected to Earth (instead of orbiting Earth) and Earth gravity forces on a pen were stronger than Moon's gravity forces, then pen would fall in Earth.
Of course you and I know that there are no such strong materials for that Earth-Moon stick, but that's yet another level of complexity that most people don't have to know about.
Technically that's true, but it would require a completely different scenario. Earth's gravity is miniscule at that altitude. For the moon to have a weaker force it would have to be so small that it would likely not even qualify as a moon any more.
http://en.wikipedia.org/wiki/Roche_limit
You can disagree all you want, it's not because things would just fall towards the moon in practice that it's impossible that the pen stand still.
"Please select all possible conditions under which pen on the Moon would not fall on the ground".
They may not be stupid, but that's pretty much the definition of ignorance.
The interesting part is the discussion of what these wrong mental models look like and how you can teach a correct one.
Absolutely. There was much they did not know, as is true of anyone. "Ignorant" is not an insult, it simply means you do not know something. Would you say Aristotle and Newton knew everything about everything? If not, then they would be, by definition, ignorant of the things they did not know.
By modern standards, absolutely.
By your definition they're ignorant, but not stupid?
The moon has less gravity than the Earth, so a pen is like a feather.
Blah blah atmosphere electro-magnetism blah, the universe is big ad complicated.
They float away because air currents exert forces on them that are greater than their weight. Eventually, in a still-air environment, the feather and the dust will settle to the ground. You can verify this by going to your nearest attic.