The developers put the feature in because some very vocal players demanded it, not because it was critical to bringing the servers to stability- which they had already mostly achieved after the first maintenance.You're making a measurable claim here. What reason do I have to trust you over the actual developers?
It's a simple fact: An active player performing actions has to communicate more data with the server than one that isn't doing anything. Your S / R network information are higher when you are active than when you are not. While there are a limited number of connection slots avialable, we didn't seem to be hitting them last week. If we're not hitting that limit, there is no reason to kick people. A better method, if people were to insist on kicking people, would be to simply kick the longest idle people first, if and only if the servers reach like 95% of capacity, rather than kicking people after an arbitrary amount of time. That is to say, kick people if and only if room needs to be made, not just because the've been there so long.