I am curious as to why some people interpret TNG as preachy, and others don't.
Season 1 of TNG is infamously full of monologs about how shitty 20th century humans were (i.e. the audience is currently) and how great the 24th century people are now. And then how much a given planet's race is like the 20th century humans, and thusly how great the 24th century humans are in comparison.
True, season 1 poured it on heavily and usually in places you didn't expect.
You could find it in the ordinary non obvious dialog and not just the famous ones everyone know about.
One way I interpret if a scene is preachy, is if the person's face turns serious and stern when talking about what should be a light subject .
When Picard explains what Starfleet is, he could have laughed and said, "Silly, Starfleet is much more than that!"
Instead, he looks very offended and with a stern look says "Starfleet is NOT
And then there's the unasked for extended commentary on a simple topic
RIKER: From what I have already seen of our "guests", there is very little to redeem them. In fact, it makes me wonder, how our species ever survived the twenty-first century.
So far all we saw a greedy man, a funny, polite country drunk, and a scared woman.
I think what Riker said was true in general, but as far the guests were concerned that was harsh.
Implying that all 24th century humans were fearless, unselfish, intelligent, with no psychological issues whatsoever.