I wouldn't say drama is necessary, but artistic merit yes. It's just when you say something, pathos generally comes along for your characters. Well maybe drama is vague enough to always be applicable.

An example of what I'm trying to get at is the Fleischer Superman cartoons, who were occasionally "woke" for its time. Betty Boop was pretty much always sugar-sweet but liked to call out modern-day conventions and helped pioneer applied rotoscoping. Fantasia. Pink Panther played with viewer expectations in often really clever ways, especially with color. Then there's proper satire series like Rocko's Modern Life, which had episodes that would call out things like how the justice system is ripe for abuse.

On the other hand, Hey Arnold! is not an adult cartoon despite drama. It is entirely from the perspective and for the mindset of youth. It's still watchable for good writing and some pretty universal nostalgia hits (as in, urban legends, childhood general shenanigans), but its voice is directed primarily to children.

I keep saying that censorship, while it does restrain one's freedom of speech, is actually somewhat beneficial to artistic creativity. If you're subtle enough you can still say just as much, as long as your audience gets it. That takes skill. I think that when the creator has to jump through hoops to convey an important yet difficult message it does make it smarter, more memorable and more genuine. It's not really surprising that adults find some children's series more interesting, seeing how these often manage to say more with less.

Being able to (and being encouraged to) say anything and everything, in turn, inspires some creators to do just that. They drown meaningful content with loads of crude stuff just because there's no one to stop them. It becomes a contest, which involves being more controversial than the other guy, just to get that 15 minutes of infamy.

And no, I'm not promoting censorship itself here – reinforcing it now would probably be a bad idea. But I'm sure that showing some restraint in the messages and how they are presented would be beneficial to the artist, the viewer and the stories.