Very, VERY volatile subject, and i'm not gonna go there. I'll just say that it depends on the individual. Almost all religions declare atheism and other religions as heresy (which, by old laws, is punishable by being burned on a pyre or stoned to death), so it's up to the person to not be a dickbag, if you ask me. But if they start using their religion as an excuse and/or reason for atrocities, i would be PLEASED to see them burned on their own pyres. Killing someone because "it is <insert deity>'s will" is just as fucked up as killing them because "i always wanted to kill someone, and it tickled me fancy at the moment. Tea and crumpets?" Seriously, don't go there. Start listening to the humans whose very existence isn't being discussed.
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And these people, gentlemen, are a potential cause for blasphemy as well. The human mind LOVES to make stereotypes, so a few people of a select religion who commit heinous acts (read: al-qaeda) will inevitably put that religion in a bad light for some.