There are currently 4 tiers of punishment with the system:
1.) 10 game chat restriction
2.) 25 game chat restriction
3.) 14 day ban
4.) Permanent ban
The way it works is you start at the first tier, and each subsequent punishment moves you up to the next one, regardless of how severe the offense may have been. Because of this, when looking at chat logs, you shouldn't be asking "is this worthy of a permanent ban" but rather "is this worthy of a punishment at all?" If the chat logs are worthy of a punishment (which I personally believe these are), then what punishment you get is determined by your history with the system. Because you admit to having 2 sets of chat restrictions and a recent 14 day ban, you were at the permanent ban tier, which is what you got.
Also, the in-client reform card, as well as the e-mail, for your 14 day ban specifically states that your next violation, regardless of the severity, would result in a permanent ban, so you should have been fully aware of that.
