MerryMarigold, I was away for a while.
I see you have had answers and I don't any better ideas about why they spread as they did. However as others have said they were not the only group of believers to spread quite a way. They were just the latest. So not a unique phenomenon.
permanentvacation,
- If you do not believe there is such a thing as right or wrong, would you mind if I came round your house with a sawn off shotgun and an appointment with your kneecaps?>>
There are things which I don't like. Just as they are things you don't like. My position is that there is no objective way to say "this is right" since it always comes down to someone's opinion.
The church tries to 'trump' this by saying it's god's opinion which counts for more. Even though if you take the old testament, god does things which would have him in prison here and now.
You can say "oh but killing someone is obviously wrong" and everyone would agree on that, except that most people accept war as ok and many of us are ok with capital punishment. Also what about killing in self defence?
So you won't even get everyone to agree that killing is wrong
The only rule I can think of that makes any sense is this one.
Given that my guess about right and wrong is no better than anyone else's. The best way forward is to allow everyone as much freedom as possible to do things the way they think is right.
So killing someone is bad because it takes away their potential choices (but you may still decide to kill a madmen with a bomb/gun to stop him taking away lots of other people's else's choices). Rape is wrong because it takes away the victims choices and so on.
Any unnecessary interference in people's private lives is wrong for the same reason.
So I wouldn't approve of a law that stopped you worshipping god for example. I don't approve of compulsory worship of the current favourite god in schools for the same reason.
My whole opposition to religion is simply that I don't want it or its immediate effects forced onto those who don't want it.