Religions are fundamentally ethical? That's nuts. Christianity teaches women are less than men and you should be open to killing your child if you hear voices. Islam teaches you to cut off women's clits. A simple search reveals plenty of examples of Buddhists behaving badly.
Ethical religion? Pretty much a contradiction of terms.
I cannot defend all the killing governments sponsor to one degree or another. But, I know I'm entirely ignorant of what's happening in most of the world and simply getting rid of government all together because killing happens taking things to an illogical extreme.
I'm also not certain one can say that governments have killed more than religious conflict. Even if religion has killed fewer, it's a huge, huge number. And if that IS case, because it's a slightly smaller number, religion is OK? What's your cutoff? Seems awfully arbitrary.