Yes, really: not surprisingly, English "rules" (or more relevantly, English usage) is what's primarily relevant on an English-language quiz. Sometimes English adopts foreign plurals in borrow words and placenames, sometimes it doesn't, sometimes it does both or neither. It's the way it is, but it doesn't make English usage any less correct.
You definitely can't cite examples like "way of life", "village" or other English terms as examples of incorrectness when a plain examination of English usage, as defined by an English dictionary, shows them to be correct.
Getting technical (for the question about Hadrian's Wall), the wall runs through northern England, so the Picts could run riot in northern England without crossing the border.
You definitely can't cite examples like "way of life", "village" or other English terms as examples of incorrectness when a plain examination of English usage, as defined by an English dictionary, shows them to be correct.