God cannot be proven one way or the other, your point is also valid, the bible states "Let us make man in our image" showing clearly there is more than one God in the bible.

The difference is not so much the belief in a "God" but in the proposed religion, any religion is nothing without followers and the need to control those followers, hence you have the promises of "eternal life", 72 virgins, etc and eternal damnation/fires of hell for the non-believers.

So "heathens", "unbelievers" and any who do not follow "your" particular religion are considered targets. While you may quote "God the merciful" or the "God of love" the end result is the religion and it's followers are still violent, bloodthirsty savages.