Were it grounded in reality, Oracle's claim that copyright law gives them proprietary control over any software that uses a particular functional API would be terrible for free software and programmers everywhere. It is an unethical and greedy interpretation created with the express purpose of subjugating as many computer users as possible, and is particularly bad in this context because it comes at a time when the sun has barely set on the free software community's celebration of Java as a language newly suitable for use in the free world. Fortunately, the claim is not yet reality, and we hope Judge Alsup will keep it that way.
As for their brief against Google's petition to the Supreme Court[2]:
SFLC and FSF take the position that the decision below is wrong, but that certiorari should not be granted for three reasons: (1) the decision of the Federal Circuit merely mispredicts what the Ninth Circuit would do if it had been the Court resolving Oracle's appeal from the District Court's finding that the application program interface declarations at issue are non-copyrightable; (2) the decision rests on narrow factual grounds; and (3) there is no public interest in continuing to adjudicate this dispute because Google can now and could have used all material at issue under the terms of the GNU GPL v2.
What to make of this? It's a bit convoluted. On the general issue of proprietary APIs, the FSF supports Google's position. But they think the judgement against Google from the Federal Circuit court carries virtually no value as precedent, as they say in their brief[3]:
Despite the manifestly erroneous character of the decision below, the petition for writ of certiorari should not be granted. The precedential weight of a decision so evidently mispredicting the law of another Circuit is essentially nil.
Now independently of the Oracle v. Google dispute, they would prefer if Google were using the GPL license for Android. Wouldn't it be nice if the bad Federal Circuit judgment could incentivize Google to use the GPL, without affecting other cases? I think that is the tactical advantage the FSF saw in opposing Google's petition to the Supreme Court. And it might have been a good call, as Google is indeed switching to the GPL Java implementation[4].
[1] https://www.fsf.org/news/fsf-statement-on-jurys-partial-verd...
[2] https://www.softwarefreedom.org/news/2014/dec/08/sflc-files-...
[3] https://www.softwarefreedom.org/resources/2014/google_v_orac...
[4] http://arstechnica.com/tech-policy/2016/01/android-n-switche...