Most atheists don't strictly believe there are no gods. They just don't believe in any of the ones they've been told about
This tracks with my understanding of being an atheist. I wouldn't necessarily extrapolate this outwards (especially considering the prominence of New Atheism and it's general offensive positioning on any concept of a god, to the point of ridiculing believers), but yeah, I agree with it personally.
For me, my personal line in the sand would be "I don't believe in any deity as posited by humankind" (at this point in time, barring irrefutable divine intervention, shift in belief systems, etc). It's tricky, because it involves both human interpretation of the divine, which is flawed by definition (and even noted in scripture), as well as the rejection of such an existence. But that's my line. Maybe there are deities out there we simply haven't come across yet. It's all about faith and finding reason in the universe. I get why people do it, I'm sympathetic even, but I don't share in that (construct of) faith.
Is there a scientific way of knowing whether the assertion is true or not? I know when I Google "killed" and "blasphemy" the results for which religion was involved are very predictable (but of course a google search is not science)!
Unfortunately it's probably very statistically-difficult. But to even make it without being able to prove it true is the bias I was bingo-ing, hah.
Like, for some people in certain areas of the world, being killed by a follower of Islam is likely to be higher than my risk of the same. But that's because of demographics. The victim is
also more likely to be a Muslim, much like I'm more at risk of being killed by someone who is Christian, or Christian-adjacent (through into agnosticism). That's about as precise as I can make it. The question becomes whether or not you're killed
because of the religious aspect, which is more legal than it is any other kind of argument. For example, there are horrendous conflicts unfolding across the world that have a religious backdrop, but the modern conflict is
also cultural (at least) as much as it is due to differences in scripture, or offense caused in religious terms either way. Which also means it's political. I don't want to derail the thread with any explicit examples, but it should be clear that in any given conflict like that, the political and the cultural goes hand-in-hand, because of the impact religion has had either in a historical context, or in a modern one.
For a low-stakes example: England is / was predominantly Christian.
Anglican apparently (Wikipedia link). Now as it stands I have a pretty low chance based on my life experience to be assaulted by an Anglican, or even a Christian, on religious grounds. But that is / was the status quo. Our cultural history is shaped by it (to the extent that everybody knows about Henry VIII and the Church of England, it's very well-covered in school. Or used to be at least).
So it comes back down to individual motive, most of the time. And when people say "I'm more likely to" (or less likely to), that's normally just because of in-group / out-group dynamics (plus bias, etc). Narz may think he has more to fear from a Muslim person than a Christian person, but if he
were Muslim (or Hindu, or had different physical characteristics that set him apart visually), he may find he has a different opinion.
Certainly (and this bit isn't aimed at Narz because I don't know a huge amount about him), but if I lived in the US, my personal worry on that score wouldn't be "Muslims".