I can only speak for myself, but I drastically simplified things down to 'If it doesn't hurt anyone, it's probably ok' Just because a very old book says that X

I can only speak for myself, but I drastically simplified things down to 'If it doesn't hurt anyone, it's probably ok' Just because a very old book says that X, Y, or Z is sinful, doesn't mean those actions are immoral if there's no harm to anyone.