That index is complete and utter bullocks. UK better than US? Hardly. The UK can and does prohibit all sorts of "news" from being published, especially about the Royals, yet it ranks significantly higher than the US. This is an OPINION survey, not actual reality survey.
And the US took the lead in oppressing news from the front lines under the guise of 'embedded reporters' and Pentagon 'consultants' in news rooms. One country censors gossip column stuff, the other war reporting. Mind you, most countries have followed the US's lead in this including the UK.
Sorry, but people who hate the US will always rate it lower than other more oppressive regimes simply because of hate.
Reporters Without Borders hates the US? Why? Actually, since it's based on feedback from reporters around the world, who tend to have a little better insight into freedom of the press, I believe your suggestion implies that reporters hate the US.
There's lots of other surveys out there if you'd prefer - but you are unlikely to find any credible ones with the US at the top.