They certainly can be
wrong. They just can't be overruled by anyone except future members of the same court. In this sense, they are not always
right, but they are always
correct. If they were always
right, there would never be dissenting opinions from 8-1, 7-2, 6-3, or 5-4 splits.
We just pretend that they, like the Catholics pretend for their pope, are infallible. At some point, you have to let the matter be settled in a final and lasting way, otherwise nothing can get done. It is sometimes better for a matter to be settled in an unsatisfying way than it is to have any uncertainty remaining.
A ruling from the ultimate arbiter is not an ethical mandate. While one can hope that their decision is compatible with and motivated by moral values and ethical principles, it could also be the result of political expedience or a bit of bad pork in yesterday's supper.
It isn't right or wrong. It is simply what has been decided by our most prestigious professional arbiters.
If you don't like what they decided, you can accept it and move on, or start petitioning a legislator in an effort to make their decision obsolete.
...Or, there is something else you could do. It rhymes with "abhorrent". As long as we're not concerning ourselves with "right" or "wrong" here, we could simply accept the precept that if the courts fail to deliver acceptable results to the litigants, they might seek them out by other means. It really depends on how mad Aereo is about the fact that a private business interest was able to use government power to destroy a potentially disruptive competitor.
I would guess that the vast majority of Aereo's business expenses were a direct result of attempting to comply with the law, and its apparent loopholes. The service could be replicated at lower cost by one antenna per broadcast station, local resources to convert the signal into compressed video files, and redundant servers in multiple safer jurisdictions. The successor could simply take subscriber fees to ensure that a particular station is recorded during a particular interval, and the resulting video is seeded for a minimum period of time. Now that they know that their entire business model is ruled illegal, there is no particular reason to comply with any part of the law... other than their respect for the law.
Aereo may choose not to do this, but they have proven that there is a market for it, and nothing excites the black market more than a proven demand for an illegal good or service. What's more, the black market equipment will be virtually indistinguishable from legal gear, so long as the operators take even the most rudimentary steps to cover their tracks.
The people who used Aereo aren't just going to go back to cable. They are simply going to move from a provider that could be sued out of existence to one that is effectively invisible, or withhold their money and wait for something else worth spending it on. I understand that the cable companies had little choice but to attack Aereo, but they have to understand that they created the market conditions for Aereo to appear. As long as they exist, they will be playing whack-a-mole with every new service that tries to provide television services better than cable.