Yes, Westerners are always evil.
On a comment to the thread subject- put it this way- even if gunpowder was not invented yet, land mines are still something which could be invented.
Davinci (another evil Westerner) invented the helicopter (or was it Zhuge Liang again??), without ever having seen a "wing" in action, so Zhuge Liang could have thought "if there was an explosive material, we could use it like so" and invent the land mine.
However, I would say that a lot of inventions attributed to Zhuge Liang sometimes dont have a 100% historical base, so not everything in a text book which says "Zhuge Liang invented this" is going to have a totally solid evidence base.
It's safe to say that he probably did invent a hell of a lot of stuff though!