What you say is true, but doesn’t really answer “Could someone take down Wikipedia [without completely shutting off the internet]”. For obvious reasons, shutting internet access completely off isn’t going to happen short of an insurrection or a war.

Shutting down Wikipedia specifically is much harder. As others have pointed out, there are many thousand copies of Wikipedia lying around on peoples private devices. If Wikipedia were actually taken down (blocked by the government in some sense) hundreds of mirrors would likely pop up immediately, and it would be more or less impossible for the government to go after each individual site that some person decides to host, short of just cutting internet access completely.

I’ve been doing the same thing, went back to read it now, and I have to admit I had a good time. Even though it took time to manually turn my comments into gibberish, it gave some hilarious results!