Atheists, tell me, a Roman Catholic: why should I become an atheist?

[Tonus]

4) Are those two somehow mutually exclusive?

A being of incomparable power and wisdom would not need war. That he chose to personify it implies a primitive approach to dealing with people.

6) Every day at a Catholic Mass, god is referred to as "Lord God of Hosts", which is the same thing as "Lord of Armies".

I was referring to the difference between the forceful persona in the OT and the gentler one in the NT.

7) Exactly. God revealed himself progressively through the Law and the Prophets, and finally and fully in Christ. There are several difficult passages in the Old Testament when considering god as love itself. But there are more passages in the Old Testament that pose a difficulty for the caricature of god in the OT as totally opposite to the god revealed in Jesus Christ.

But he is, as I noted above, the almighty. He doesn't just fight battles, he personifies military power and overwhelming strength of arms. At various times he not only kills --or orders the killing of-- soldiers, he sees to the death of entire tribes and even their livestock, and in some cases even their valuable goods (an order that was so strict that he punished Israel when one man tried to hide some items instead of destroying them). At other times he allows the taking of wives from among the virgin girls who have just watched their families massacred and their lands ravaged. He gives instructions on how to demand that a tribe surrender to them as slaves or face annihilation. This is not a god whose people are being forced into war... he is imposing genocidal levels of destruction on entire cities so that his chosen nation can take the land.

I think it's fair to consider this as being totally opposite to the version that is the very personification of love.