I agree with him that UFO crashes are a silly notion but we have different reasons. If, however a species conquered the massive task of interstellar travel, they wouldn't be crashing. Not even their teenagers.
What he misses is the undeniable reality that at least a large percentage of travelers would start with self replicating probes and radio and other signals before that. In order for them to "hide" they would have to chase down all their signals and probes before they reached us or anyone else and cover their tracks. And if there are thousands of societies out there, they would ALL have to do the same thing every single time. This is not realistic.
It isn't the greatest analogy but if humans decided right now as a species to hide from ants, could we pull it off?
You know the best way to hide? By not existing in the first place.