Yes and no.
You are right that this should be added to that thread and the code should be offered as an alternative.
So the text in it is OK, because it is correctly explaining what is happening (and why) and also what happens if you change the pulldown to a pullup.
It just doesn't tell you about internal pullup and the advantages to it.
I think (so i'm not sure) you can do that yourself, or else request this to be done while offering the text, pictures and sketch to get it done.
Do you realize that this page and the sketch was aready created 8 years ago ?