Should The FBI Be Reading Suspected Terrorists Miranda Rights?

While on the ground at the U.S. base detention facilities in Bagram, Afghanistan Congressman Mike Rogers(R-MI) discovered that FBI agents are reading Miranda Rights to terror suspects.
The Department of Justice Dan Boyd has confirmed this.

Boyd stated:
"There has been no policy change and nor blanket instruction issued for FBI agents to Mirandize detainees overseas. While there have been specific cases in which FBI agents have Mirandized suspects overseas, at both Bagram and in other situations, in order to preserve the quality of evidence obtained, there has been no overall policy change with respect to detainees."

This policy was started under the Bush administration.

Rogers, a former FBI special agent and U.S. Army officer, says the Obama administration has not briefed Congress on the new policy. “I was a little surprised to find it taking place when I showed up because we hadn’t been briefed on it, I didn’t know about it. We’re still trying to get to the bottom of it, but it is clearly a part of this new global justice initiative.”

The FBI claim to only Mirandize very specific detainees for very specific reasons.

I don't understand why the FBI is reading Miranda Rights to terror suspects who are not United States citizens. I am against giving terrorists rights that only should be afforded to U.S. citizens regardless of which administration was/is having FBI agents do it. Are we constitutionally bound to do this? Or is the FBI using Miranda Rights as a tool in order to gain information? Is this setting a dangerous precedent? Why is the FBI only mirandizing a select few of the suspected terrorists? President Obama has just recently decided that the detainees at Guantanomo Bay are not going to come to U.S. for military tribunals. Bush never considered this to be an option either. So, then why are we essentially giving suspected terrorists rights that they are not required to have by law since they are not going to be coming to the United States?