This is copyright. Copyright holders are allowed to assign reasonable restrictions on the content they broadcast publicly in order to monetize that content as they see fit. One of those restrictions is that the content broadcast over public airwaves may not be rebroadcast or retransmitted for non-private use. If your business model is encoding and retransmitting that content over the Internet, that's not private use. Considering the entire content industry's business model is based on controlling the distribution of the content that they own, there's no way this decision could have gone any other way. If you fundamentally disagree with the content industry's right to control distribution of content that they legally own (or at least control copyright to), then you are free not to consume any of it.

I have no pity for Aereo here. They based their business model on a legal technicality, and SCOTUS simply applied an updated technological interpretation to an old law. Their investors were big time media guys (Barry Diller was a founder of both Fox and USA networks) who knew the risks they were taking: it didn't pan out for them. Aereo is not a story of a plucky startup fighting the system; it's just one part of the system fighting another part of the system over who gets more money. Had Aereo won this decision, the real winners would have been Comcast, DirecTV, AT&T and Verizon.