Why are some atheists here spelling G-d or referring to Him with a capital letter?

As you noted, in English proper nouns should be capitalized. "God" is a proper noun if it refers to Yahweh (which Christians often do), but it's not a proper noun if it refers to a generic noun. Spelling it "G-d" is just silly, as is capitalizing pronouns referring to Yahweh (like you did).

Of course, many people are not always careful and may make mistakes.

I think a lot of it would either be habit or context. Grammatically, a capitalized "God" refers to the god of the Judeo-Christian faith while "god" simply refers to any deity (ie, "Zeus is a god."). If the individual has an upbringing in the Christian faith, capitalizing "God" and any pronouns associated with Him ("Him" being the Judeo-Christian god) would most likely be habitual.

Honestly though, most people probably just aren't spending a lot of attention to what is capitalized and what isn't.

I never noticed that before. But, you should see many true online atheists spreading pure deception on the internet, and mixing up historical facts, in order to promote atheist ideology- even if comes at a high cost. They are really desperate and they need severe help. I would imagine that many suffer from schizophrenia, NPD, or Asperger's. Many of them spread hate messages and are some of the biggest hypocritical liars on the face of the world. If you go on youtube and examine every cyberbullying comment, you'll eventually conclude that almost 60% of them are atheists. Huge number eh? I had one of them send me hateful emails saying stuff like "you idiot moron. How the F... can you believe in Bla Bla Bla? I hope you die and kiss the pope's C..." I had to make another email account. :P

Also, always pay attention to how atheists are the first to answer every question on yahoo answers. TALK ABOUT DESPERATE. They're constantly wasting their time on the web in order to deceive many people. Nearly 5% of the world are atheist. They're like patrol officers on the web. Internet atheist: "Hey! is anybody asking a religious question? Alright just checking. I'm on guard 24/7. My shift ends next month..." I mean, is everyone one of them from France or China?

Regardless of whether God exists, it's still a name of a person, even if that person is fictional. Just like Santa Claus is always capitalized. Joe's Crab Shack is always capitalized. Etc. etc.

edit: Oops. We did read the details (I did anyway). Your entire question is badly phrased and easy to misinterpret.

I capitalize Santa Claus too..... so? It has nothing to do with belief and everything to do with proper English. A proper name is capitalized even if the subject is not real.

I think you're boolshitting; I don't see that at all.

"It is also amusing to watch how half of you didnt bother to read the details"

Why go the long way round?

~

I went to a Christian school when I was little. So I do it naturally. It's a habit I've never been able to kick.

On top of that, it allows the delusional bigots to see when I'm being blasphemous and when I'm being serious.

I do not believe that "Tom Sawyer" actually existed, but even the proper nouns referring to fictional characters are to be capitalized.

Sometimes I do it to specify that I'm referring to the Christian God. Or else I just type "the Christian God". Like I just did. I'm starting to fall out of practice with it though because he doesn't deserve any reverence or worship.

Since an atheist doesn't accept the concept of god - he is at liberty to capitalise or not capitalise God as He sees fit.

Atheism is about thinking for yourself. Faith is about doing what you are told to.

Don't presume to tell atheists what we can and can't do;- we're smarter than you are.