The case against the telcos is based on violations of law, not constitution. The telcos violated provisions in FISA which placed specific parameters around what they are legally allowed to do (and required to obtain) in order to perform surveillance on US citizens or within US territories. The provisions are specific enough that civil damages are specified in the actual law (per incident!) to further incent the telcos to obey the law.
The government asked for something they shouldn't have, and most of the telcos (not all!) gave up something they were legally obligated to protect. As far as I'm concerned they are both fair game.