"... to the extent required ..." would leave them open to liability related to the methods they use to implement the system; if it can be established that the service could have been implemented in any way that did not require them to expose, transform, etc., the information in question the way they did at a particular stage, they are suddenly in violation of copyright license.
No, it isn't -- trust me. An approach that seems to be the only way to do things at point A, an approach that was arrived at that was the product of somebody's best thinking, but later turns out to have only seemed so at the time it was implemented (everybody has blind spots), is still a good-faith effort. The word required means that good faith (in the legal sense) and the limits of technological knowledge at any given period in time are insufficient defense for for actions brought on the basis of knowledge that did not exist at the time of the alleged infringement. That is an unreasonable and onerous burden; the service (or any similar service) could not be provided under those terms.
