God has a lot of official names (HaShem, Adonai, El, etc), the Tetragrammton is a very specific one and a very formal one, only spoken by the High Priest at certain times in front of the Ark of the Covenent, and forbidden to be said at other times.
Now, as Christians, I know that sort of thing doesn’t apply, but it sure seems a bit rude to use the name in any other manner than directed by God Himself, so I always thought this was a wise decision.
Regarding Jews who right “God” as “G-d”, the article is incorrect. Jews are not permitted to let the name of God (however written) get defaced, so, in causual writings (like the internet), the word is avoided or written like “G-d.”*
* Learned this on FR from some of our more helpful Jewish Freepers.
There is no such demand or direction from YHWH. In fact, if you would read the law, you will see that "YHWH" is to be His name of remembrance among men - It is supposed to be on our lips. It is the name that we are to swear by.
But instead we cover it up and make it secret.