I doubt the loss of sympathy or more serious charges will make a difference in America's efforts to prosecute him. But revealing that the NSA was hacking targets in Hong Kong may make a big difference in Hong Kong's willingness to cooperate with that prosecution.

On what grounds and from whom?

The US government sees giving government secrets to foreign governments (espionage) in a different light than merely disclosing classified info to the public.

See http://www.smithsonianmag.com/history-archaeology/The-CIA-Bu...