For what it's worth, PBS has an app[1] for Apple TV, and it has much of PBS' content.
With that said, the general problem of certain services being restricted from/to specific platforms is extremely frustrating, and will only get more painful as exclusives become common.
With that said, the general problem of certain services being restricted from/to specific platforms is extremely frustrating, and will only get more painful as exclusives become common.
[1] http://www.pbs.org/anywhere/connected-tv/apple-tv/