Courts that aren’t adversarial are just interpreting law. Secrecy makes it worse by eliminating accountability by the petitioner and judge.
For a non-secret example, look at the Social Security “fair hearings”, where an administrative law judge basically listens to a petition and makes a decision. The standards vary significantly by locale.
Also that you aren't even allowed to show up to defend yourself. [1]
Also that they denied 11 out of 34,000 requests over a 35 year period.
Also that the judges are appointed by one person and don't even need congressional approval.
How could it possibly not be a kangaroo court?
[1] https://en.m.wikipedia.org/wiki/Ex_parte