Ok, I'm going to use simple words, since you seem to be a bit slow: that was then, this is now. What the US did back then does not justify what the US does now. Also, nobody is arguing for disarming the US down to Liechtenstein levels, in case you haven't noticed. But I do believe that a less armed US of A would be a good thing. In case you don't know, the US spends nearly as much in "defence" as the rest of the world combined. Also, it would, for instance, discourage the US from playing vigilante. It would also give US demands for nuclear disarmament and nuke control a lot more legitimacy.
Canadian defence spending is comparable to the defence spending of other NATO countries. It's the US that spends too much on "defence". Canada shares a border with only one country, the US, its major business partner. Presently, there are no major powers capable of seriously menacing Canada, militarily speaking. China is not an immediate danger. If China is so menacing, why is it then that China is the US's second greatest commercial partner, right after Canada? Present day security problems come from terrorism, and large conventional armies are pretty much useless against terrorism. Nukes are even more useless.
I believe that Canada does not need US "protection". But since old habits die hard, the US will keep giving it anyway, even if most Canadians don't care.