Different people, different rules

Compare two confessions, one is taken at its face value and the confessant is convicted based on that confession alone. In the other case the confession is not believed in, corroboration of confession is sought, and ultimately the confessant is told he was lying. We are talking about the way the judicial system handled Hamid Hayat and John Karr’s confessions. John Mark Karr confessed he killed JonBenet Ramsey, but the judicial system said, ‘No, John. We are not going to believe you. We have to independently verify your claim.' A DNA test was done; the test came out negative and John Karr was off the hook, at least on this count.
And then we have the confession of Hamid Hayat that he attended a terrorist training camp. But in this case nobody bothers to corroborate. No evidence is shown if the camp really existed, if Hamid Hayat indeed got training during the time he said he was there. The confession is believed in, even when the confessant said the confession was obtained from him, under duress.
Who says Justice is blind?