This issue came up a few times before in discussion on Hacker News. A little known fact is that "facts on the ground," even entries in reference books or labeling on maps, can be taken in international law to indicate acquiescence to territorial claims by other countries (or to indicate assertion of hostile claims by the country in which the reference books or maps are published). This is why some countries with extensive programs of censorship censor maps, dictionaries, encyclopedias, websites, and whatever else is in reach of the government censorship program to make sure that private publications fall in line with the government's official position on territorial claims. (I have in my home office English-language and Chinese-language reference books published in Taiwan during the period of the military dictatorship there, which censor references to the existence of the independent country of Mongolia and assert province names for the mainland region of China that have been obsolete since 1949. Taiwan has since considerably loosened up on this kind of censorship after democratizing, but territorial claims vis a vis China are still a very sensitive issue.)

In countries without official programs of widespread censorship, government-published maps of other countries will still say things like "Boundary representations are not authoritative" and private publishers of maps in free countries will have notes near disputed boundary lines like "actual line of control; boundary in dispute" and so on. This is a pretty big deal in international law, so it is a somewhat big deal that Google, a business corporation organized under United States law, has changed its indication of the status of Palestine, even if only for the Google domain registered for the .ps top-level domain. The United States government may feel the need to make a formal statement to the effect that this action is the action of a private business corporation and does not represent an official view of the United States government.