I do not know for sure... but I'll take an educated guess and folks with more knowledge of Judaica can correct me.
The original Hebrew name for God (tetragrammaton) did not have vowels. Also, if you trace back the origin of this practice back through the Talmud to the Pentateuch, you will find that one of the ten commandments says that we should not misuse (take in vain) the Name of of the Lord God.
For these reasons, it is probably a combination of integrity to the original language to omit vowels from the english version for God and may also reflect reverence for the Name as being special... to not speak or spell it in its entirety. If you do not speak or spell it in its entirety, then you will not misuse it -- either intentionally or mistakenly. Here is a reference...
http://pages.cthome.net/hirsch/tetra.htm
As for the including of Christians inthe title of this thread, it always amazes me that the most frequent reference to Jeshua in most current movies and books is as a curse/expletive. I wonder if people using this name in such a manner ever stop to think about why they are doing so and what the significance of that is? Probably not.
Anyway -- Best wishes for a Happy Hanukkah to the Jewish members of DNForum and all who join them in that celebration!
Jeshua, who was Jew, celebrated Hanukkah (John 10:22).