The guy was on their spaceship and they are worried about secrets being given away? I would think any aliens would already have access to lots of "secrets" if that's what they wanted, whether from outright spying or mind reading.

The only secret I can think of that they wouldn't want aliens to know about is that they plan to attack them or screw with them in some way.

It must be pretty frustrating for higher intelligence to watch us screw up so badly and not help us. This is understandable, we have to learn. We couldn't keep getting bailed out and expect to advance to a "Golden Age" civilization.