That is true, but the point of the post is that people don't make these kinds of arguments in real life. If I say "yesterday the bottom of the sky was red, and I know because my brother told me and I don't think he would lie to me". This sentence reflects real life more because you example is based on the absurdity of someone arguing a known universal truth, that creates the exact kind of toy sentence example that can then be easily discredited.

Just pointing out a fallacy is not enough, you also have to be able to show how that fallacy discredits the argument as it is used. People commiting fallacies are just doing a quick patch job on a structure that is their argument. And as any patch job it can be just fine, ugly, or it can be a life hazard.