The reason we banned CN was that many people do not understand the point you make in your second paragraph. A lot of people simply take CN to do whatever they want, whenever they want. They do not realise that while CN is all about freedom, it is not about killing, murdering and backstabbing innocent bystanders and to accept collateral damages without remorse. This is the province of Evil.
And again, many that takes the CN were hoping just that. Hey! I am not evil. But I can act like one if needed of if it suits my current mood...
With such stable groups as I have now, I might and probably should reconsider my/our stance on CN. It might add a few more RP opportunities. I'll sure bring the topic for the next campaign.