This is the best episode I've seen. It's not exciting, but it is compelling and heart felt.
It reminds me of what good scifi can be, exploring difficult questions and forcing characters to make hard choices, all with their beliefs being in conflict.
It doesn't preach at the audience, and it doesn't insult them or talk down to them. Whether or not it "teaches a lesson" depends on who you ask. I'm sure that even among viewers who would agree it had a lesson, many viewers would disagree entirely on what that lesson was.
I definitely think there is a valuable takeaway for the viewer here, something about arrogance, perhaps something about shortsightedness.
Some kind of deeper wisdom is subtley on display.
Every member of the audience will have to decide, on their own, what that wisdom actually is.