I don't agree, but so be it.
This topic was thrashed out quite thoroughly at Balloon-Juice last night - http://www.balloon-j...reedom-thats-why/
1) Greenwald released information about GCHQ spying on a G20 meeting. The UK authorities have an interest in protecting information that they have classified.
2) The UK law in question was passed in 2000 and has been upheld as being sufficient authority to detain people who aren't engaged in terrorism.
3) Greenwald has said Miranda was carrying classified information that he got from Snowden. The UK is under no obligation to let unauthorized people carry classified information, which likely includes their own classified information, across their border.
4) Miranda wan't held beyond the time period the law permits.
One can dislike the overreach of the various security laws without thinking that Miranda was improperly detained. Especially when Greenwald bragged about Snowden taking information on "sources and methods".
'I think it would be harmful to the U.S. government, as they perceive their own interests, if the details of those programs were revealed,' [Greenwald] said. - http://www.dailymail...NSA-operates.html
FWIW.
Cheers,
Scott.