This is a huge win for anyone hosting data that falls under Japan's very strict privacy and data export restrictions, and shows Linode is definitely competing for space in the professional hosting market.
Since Linode is a US business, the government can still request data that is hosted on these servers, regardless of Japan's strict privacy restrictions.
I think you are misreading that comment, in that it isn't about whether the US can get to your data, it's about whether you as a provider can meet the Japanese laws with a US datacenter.