Knowingly exposing sensitive government information is a crime. Anyone with a security clearance knows that (or should know that) because it is beaten into you when you get a government clearance.
Subpoenaing Private Manning in this case is not unusual. He is involved in a criminal investigation.
I am not familiar with all of the other names on that short list. The ones I am familiar with are not US citizens. Non US citizens outside of the territory of the US do not have any of the same rights that US citizens have. (Non US citizens inside the territory of the United States have very many rights). Subpoenaing the records of non-US citizens that are currently not located inside of a US territory is not against any law I know of. IANAL, please someone that has more knowledge clarify that issue.
Also, the US government does do things I do not agree with. Bringing up a list of bad things the government does/has done and tying it into this, when there is little relation, does not help your cause.
There is a catch-22 situation of exposing government bad stuff. Most (but not all) government bad stuff is classified, not necessarily to hide the government doing bad stuff, but for other security reasons. If you really want more of this to come to light, support more political candidates that support greater government transparency. Texas Senator Ron Paul comes to mind, but before you blindly support him because his views on say US foreign policy and the economy align with yours, investigate the whole man and all his beliefs (he is extremely conservative. More so than any other Republican conservative).
Also you say "your country" so I assume you mean that you are not a US citizen. The problems of the US are best solved by US citizens, but unfortunately most of us can't be bothered to stop and think about our government.