@Beau Skunky  
She cares about appearances, so she’d probably care more that a bunch of “lowly farmers” and their friends were allowed to get away with “bullying” her daughter than any actual harm done to DT.

@Spiritus Arcane  
There’s also the sad possibility that Spoiled probably wouldn’t care, ‘cause honestly she doesn’t seem to care about her daughter enough.

@Beau Skunky  
Filthy might be reasonable normally, but Spoiled is a weapons-grade mega Karen, and people like that don’t understand consequences so it wouldn’t surprise me that she’d be willing to bully Filthy into it.

@Spiritus Arcane  
Filthy seems to have a good relationship with their family, and as an episode shows, he’d lose alot of his business/money (and upset his grandad) if he ever severed business ties with the Apple family, so that would bite them back too.
 
@TexasUberAlles  
Might not be a good idea, if say the bully is bigger/stronger then you, (even fighting dirty like that won’t necessarily give you an upper hand) or making them crave revenge after you hurt them. (And they could do worse things out of revenge, like spread rumors about you, try to give you a bad reputation, and such. A girl did that to my sister in school.) So honestly, I disagree violence would work for every situation, as oftentimes it just creates a back, and fourth revenge war, rather then “end” things.

The really cynical view on this is that AJ does nothing because she’s too afraid of pissing off the Riches and losing their business.

I was 100% down with the CMC building a deathtrap for their tormentor; “just tell an adult lolol” has been absolute horseshit since forever, because adults do not give a FUCK about kids’ problems if those problems force adults to acknowledge their own complicity in making the problem happen in the first place. The only correct way to deal with a bully is to step up and fuck their shit all the way up; go for the eyeballs, go for the regular balls, go for the neck, go for the kneecaps– just the maximum amount of violence that you are capable of bringing, and do not stop until someone much bigger than you drags you the hell off of them. It is literally the one and only single way that the little fuckers can be made to understand that continuing to harass you will get them Hurt For Real.

@Myoozik  
But why wait as long as she did? Especially if it undermines the intended lesson?
 
@DarkyBoode32  
It’s not like DTs mother is the one responsible for her being a bully, right? It’s like they realized the Aesop didn’t work and ignored it.
 
If AJ did intervene Babs wouldn’t have been able to do anything to show herself deserving of redemption and how would it have changed the series for the better if DT and SS stopped having the means to be be antagonists before “Crusaders of the Lost Mark”? And if they weren’t in this scene would fans complain as much about them being Karma Houdini’s like Suri (despite that adding to the Aesop that other may exploit your generosity and even get away with it but don’t stop being generous)?
 
This was written before they knew the show would continue past this season. If this was the end of their bullying it would have been just a flaw in an Aesop otherwise seen as worth it. It’s only after Season 4 I noticed serious backlash against it.
 
I won’t defend this moment but I will say it’s worth asking why the writers thought it a good idea despite the OBVIOUS flaws.

To be fair, I think she was gonna say something until Babs stepped in

Because Applejack knows it’s happening, and Babs did threaten Diamond Tiara and Silver Spoon that she’d tell their mothers in that scene.

@Background Pony #F86C  
By that logic, the CMC should be teenagers too. I think that shows the EqG characters aren’t the same age as their pony counterpart.
 
Plus teenage ponies (like Teen Applejack, and Plaid Stripes) have been shown to be shorter then adult ponies.

@Background Pony #F86C  
A teenager with her own business? Don’t talk rubbish.

If we consider her EQG counterpart she may be a teenager…