Rabbitoid, regarding your point that Congress, not agencies, should do this, the courts have long supported the opposite conclusion, for the stated reason that executive agencies pool subject matter expertise from industry, academia, and the concerned population at large in a way impossible for Congress to match, and with the ability to write detailed regulations and hold administrative hearings to resolve problems of a volume that would bury both Congress and the Article III courts without those mechanisms.
While it is a valid point as far as it goes, my somewhat-more-cynical point of view is that the best point in favor of the agencies is that Congress is usually dominated by a bunch of corrupt weasel bastards with little or no technical education on anything useful, and big money talks big there, much bigger than mere facts, or law, or right. Which is why copyright law coverage has been extended and extended again to effectively multiples of what it was at the start of the Twentieth Century, and has produced incredible travesties like the Digital Millenium Copyright Act.
At least with respect to the phones, this decision is actually a victory for the traditional interpretation of copyright law over the present convenience of mega-corporate money interests.
