Never the less both men has something that their government didn't want the public to know. Both use government secret info as leverage in case they get into trouble. Both are seeking asylum. It's just that Snowden has far more juicy data than Ling Jihua does.
Again I think you're missing critical parts here. Snowden did not just flee and hand the documents over to the PRC or Russians he Posted them online and Made his escape as public as possible.
In this case, we have a individual who took the file, smuggled them to his brother, was arrested and his brother gave the files to the US Intelligence services, he didn't hand them over to Newspapers or post them all over the Web.
That would be a reason someone in the US government leaked it to the media
again the assumption that the US Leaked it out. Remember that the US Media sat on this story for over a month! If the US Alphabet soup of agencies wanted the US citizenry to know of their victory, why was it a Hong Kong news outlet that broke it first followed by Australian newspapers? Why was it not on the Free Beacon back in December? Why wait to leak into a captured news cycle? If they wanted to make a grand slam dunk of victory they would want this story on the front page of every newspaper and leading the Fox,MSNBC, CNN, Blumberg, MSN, PBS, ABC,CBS,NBS, and BBC news cycles but because it hit the news cycle around the Iowa caucuses it was buried. The news cycles leads were Cruz took first Trump Faultier, Hillary Feels the Bern. Not US gets Chinese Intelligence golden egg.
I am sorry.
A US leak would have placed lines to US Media that would have feed to Hong Kong media not the other way around.
The assumption is also that the US government would have wanted this to be a know event, But if they let the world know about this then it limits the effectiveness of it. Yes Ling was already imprisoned but only the US government and the PRC knew about his brother and possible involvement. When you broadcast that you have data it tells your enemy to change there plans. When you broadcast who gave you data you make that person a target, one need only tack back a few pages to see the calls for blood.
I think this wasn't Washington, I think this was Beijing. The leadership was telling the US that they know all about the Ling dealings and that if they think they have anything really useful its expiration date is running out. They were also trying to use the events of the exchange to rally support for the continuation of the Anticorruption purges, as well as send a Message to Wenchung that they are not very happy with Him. They want to at the very least burn him from any contacts or acquaintances with any loyalty to the PRC. As well as send the kiss of Death by broadcasting him as a traitor.