Why have they only arrested Julian Assange?

Few hours ago it was reported that Julian Assange was arrested in London. His arrest is based on the rape charges in Sweden, so it is claimed it has nothing to do with Wikileaks' latest release, but it is of course very, very convenient. All we can hope for is that he is treated with respect according to law and that Sweden will not be coerced to hand him over to the U.S.

If Assange can be arrested for alleged rape, why can't the UN have Hillary Clinton arrested for espionage?

A cable to US diplomats issued under US Secretary of State Hillary Clinton's name tells them to collect "biographic and biometric" information - including iris scans, DNA samples and fingerprints - of key officials at the UN.
The diplomats are also ordered to find credit card details, e-mail addresses and passwords and encryption keys used for computer networks and in official communications.
The officials covered include "undersecretaries, heads of specialised agencies and their chief advisers, top SYG [secretary general] aides, heads of peace operations and political field missions, including force commanders".
At least nine similar directives covering various countries are included in the Wikileaks release, both under the name of Mrs Clinton and her predecessor, Condoleezza Rice. Source

What would happen to Joe Bloggs if he did the same thing as Hillary Clinton? Do we actually dare to think of that?

What kind of example do this set for our future generation? If you are a politician you can do whatever pleases you, but if you are Joe Bloggs you better ask how high when the politician tells you to jump. Is that really the message politicians want us to receive? Do they really think that will keep people from trying to find out what the governments around the world really are doing? No wonder the state of the world is what it is right now when we have role models like that.

It reminds me of the good old contradiction: "Do as I say, not as I do." Kind of like when a parent lights up a cigarette, takes a big puff and tells the kid that only idiots smoke. It just confuses the poor kid and teaches them nothing -- other than to not listen to their parents.