how come?
I think the point the original comment was trying to make was more that NPR doesn't have much in depth coverage when it comes to science. You'll think NPR does an exemplary job when it comes to content you don't know much about. But when you're more knowledgeable about the field being covered, you start to see minor inaccuracies to "dumb down" the concepts.
Which isn't a bad thing necessarily, it gets the point across without being too wrong.
I do not see any way around news sources being simplified, to some extent, about everything, and you appear to agree. Do you think NPR's news is notably "not great" in that regard? Its liberal bias shows, but not in a way that strikes me as deceptive.
There have been some stories on NPR (and most news sites as far as I can tell) that I've felt more knowledgeable about, and realized things were being simplified to make it easier to digest.
I guess another way of putting it would be that at first glance, you think NPR is awesome, and does a great job of covering the news. But then at second glance, you realize that while not intentional, it's just not as detailed or complete as you'd like it to be.