@Dustcan  
He threatened to cut ties, sure, but it was back when he was inexperienced in running a business. Spoiled talked about him running the place like it had only just happened. Plus, he thought Applejack lied to him (before she actually did), making her a bad business partner as far as he knew. He made mistakes. A little later, he was shown being sincerely concerned about Granny Smith’s health.  
More recently, Filthy Rich has been shown donating money to rebuild a playground, apologizing for what he thought was an honest mistake on his part (which turned out to be Apple Bloom’s) and it’s implied that his dealings with the Apples are and always have been fair and mutually beneficial.
 
@Cyborg_pony  
Because writing “rich” and “immoral and uncaring about the environment” interchangeably is easy and most readers won’t object to it.

@Cyborg_pony  
He is nice but his cutiemark also say that he is a business pony with a demand that he need to fulfill. You can’t go against somepony destiny or other ponies necessities/job
 

Rarity and Rainbow confirmed for hating nature.

Well I was worried they’d go full eco terrorist with the message but at least they’re being nuanced.

Applejack cracks me up here.
 
 
@Cyborg_pony
 
The same episode had his opening scene giving a speech where he basically says “I run pony Walmart”, as well as a flashback episode showing he was willing to sever business ties with the Apples because Applejack, as a teenager and not the head of the family business, waffled on his experimental business idea. And that’s not counting the human world counterpart’s actions.
 
Guy’s a responsible father but a cutthroat businessman.

Why do they always make Filthy Rich a dick, when it’s been shown in the show he’s a pretty cool guy that understands the Apple family’s traditions and obligates them.
 
He even forced his daughter to learn, because she’s eventually going to take over the business.

Industrial Sabotage/Espionage cutie marks would be kind of cool. Maybe Twilight can let them borrow her William Gibson collection.