toujoursmiraculous:

Yes, Adrien telling Marinette not to pursue exposing Lila may seem like he wants to just let her continue her behavior and thinks it’s okay that she behaves like this, but that’s not what I take from it at all.

Just hear me out.

“If you humiliate her, she’ll just be hurt more. Making a bad guy suffer has never turned them into a good guy.”

This is very true. Lila will retaliate. She’ll get more angry, and do even more damage. She is not the kind of person that will see the error of her ways and attempt to change. Obviously enough has been done since Lila is so against Marinette, declaring war with her, but now Marinette will stop with this approach because it’s getting nowhere and is just making her look bad. He’s doing her a huge favor by saying this.

“So we just stand by and let her lie?”
“As long as you and I both know the truth, does it really matter?”

Ugh my shipper heart. That line got me. You and I.
But in all seriousness, just the fact that they know, it really doesn’t matter that the others don’t. At least not yet. Marinette warned everyone, and they chose not to listen. That’s their problem. If Lila tries to pin Marinette’s friends against her, Adrien knows. He’ll defend her and try to get them to see reason, and if not, he’ll be there for her.
And because they both know, they could find a way to make everyone see the light without going the aggressive route. This episode was designed to set up the season, not to be resolved in an episode.

And one day, Lila will be exposed exactly for what she is, and the class will have some serious guilt to deal with, and maybe learn a important but hard lesson.

The contrast from the end of S2 to the beginning of S3 is actually pretty major. It was Adrien who gave the speech about how wonderful Marinette was. Nobody else even said a word. They’re trying to show that the other kids pretty much take Marinette for granted, because I bet Adrien had a huge part with the picnic in the first place, given his speech and thoughtful nature. Now it’s Adrien that’s the only one completely on her side, and trying to keep her going in the right direction instead of letting her stray off course. They’re showing us that Adrien’s there for Marinette when she needs him most and shows her his support in whatever way he can. To viewers, it may not be in the most ideal way, but he’s also being true to himself. It’s also a gateway into him realizing he cares about Marinette as more than just a friend.

Lila may think she’ll be getting what she wants, but in the end, she’s actually helping Marinette out.