It occurred to me now that these plot holes have become more frequent in our era of serialized storytelling. That's because we have multiple writers involved in multiple episodes and then they all get confused and fans point out the glaring plotholes. See also the current dilemma on how Spock was going to save Romulus by destroying its sun (due to multiple writers disagreeing on where said supernova was).Exactly. I mentioned this in my original grievance list above. He has a room full of dead Romulans, only one of which is disintegrated. That would be the time to get back on the horn with some authorities.
You could argue Picard thought more were coming. Rios stated "things are getting hot up here." That doesn't much help Laris and friend. What do we assume happens to them? More Romulans come to finish the job? They're left alone, dispose of the bodies, and cover the incident up? They contact the authorities and try to promote Picard's conspiracy so that backup can be sent? My guess is the in-show answer will be: forget about it.
TOS and TNG didn't have these problems because they weren't serialized. The writer only had to worry about his/her episode alone and that was it. And if one episode had an error, it didn't affect all the rest like a chain of dominoes because the stories were standalone.