I can’t believe anyone would think this issue turns on the question of whether God exists or not, or that a person could imagine they could justify offending intentionally offending someone else on the grounds that God is a fiction.
Bill, you hold the name “God” in high esteem because of your religious beliefs, but you must realize that not everyone holds those same religious beliefs or degree of esteem. And they, like you, are allowed to say whatever they want, in whatever terms they want.
The question is one of politeness, not one of religion. If people know you and your beliefs, and respect you and your beliefs, you might imagine they would refrain from saying things they might reasonably be expected to know offend you. But if they do not know you, or do not respect you, or do not care about your beliefs, or do not feel that the discomfort you feel is large enough to curtail their self-expression, then they cannot be expected to moderate their means of expression in order to please you.
I am not Jewish, I am Christian. Many Jews on the Board refer to the Diety as “G-d” because they take the prohibition against using His name to include the term “god” as well as those words that others consider “names.” I do not believe this. I write “God” because I do not personally believe “God” is God’s name. Do I offend my fellow Jewish posters? I sincerely hope not, but even if I do, I am not willing to moderate my use of the word to reflect a tenet I do not hold. Maybe this makes me impolite, I don’t know; I hope not.
On a message board in particular, you cannot hope people will refrain from doing things they know or reasonably ought to know are offensive; sometimes people intentionally offend because they want to be “shocking.” I’m sure Jab is well-aware that his signature is quite likely offensive to a number of Christians – to Catholics, perhaps very offensive – yet he uses it anyway.
Your choice is to bite the bullet and overlook the mildly offensive in order to participate in the forum, or to decide that it is not worth it to participate and withdraw, or to ask that people refrain. You have chosen the third option, and they have responded by refusing to refrain, which of course they are free to do. How you deal with that information is up to you. Personally, I’m happy enough here to overlook a lot, but then I’m not personally offended by the use of “God” as an expletive. In fact, I’m worse than most, because I use it myself and I, as a believer, know I should not.