I think it should be comparable. The Atheists and Christians of the same country.
except when there are religious laws. Because those laws are made to oppress Non-believers.
The stats are not right. The peace index is so positive in some countries, because they have not that much military. And that is the same reason why the USA is worse because they have military stationed in Europe and around the world and therefore a high cost.
Jesus has abolished slavery and the cruel laws. Islam defends Muhammed no matter what he has done. So slavery is either something good or they do not talk about the topic. And Muhammed as a person is not condemned for this behaviour.
Sexism is normal in Islam. That is also the case in right wing Christianity, but not that intense. You are not allowed to beat your women as far as I know. That is something the Koran encourages and allows for educating the wife and therefore it is done by right wings.
Right wing Muslim countries and right wing Muslims kill people that abandon Islam. That is not a law in Christianity. In Islam it is a law. But people that convert to Islam do not get killed in Sharia countries.
So it is a Muslim superiority law. There is no equality.
In right-wing Christianity, you should love everybody, because of the law "love your enemies" and "love your neighbor as yourself". In Islam, you sould only love your kin, the laws of love do not exist there and you should treat Muslims better than others. There are a couple of laws in the Koran that show that. That is a open xenophobic behaviour. Muhammed was a cultural racist. Jesus was the opposite.
Muhammed was a violent mass murderer and he preached hate against everybody exept his own group. And that behaviour is viewed as something good, because they see Muhammed as an example.
Jesus preached non-violence, also loved the outsiders of society and the enemies.
I could go on and on. But you would not read it. The greatest differences are in the behaviour of Jesus and Muhammed. Muhammed has violated nearly every human right and was a slaveholding imperialist, colonialist and a disgusting person in general. Jesus was nearly without flaws.