These two are the worst kind of people, any cuteness they might have is underminded that they made fun of and torment a pegasus who couldn't fly. That's making fun of the disabled! They made fun of crippled pony!

Agreed. I'd like to think they're not beyond redeemable yet, but yeah...worst ponies.

While I do agree with the both of you, consider this:
Perhaps Silver Spoon is in the same situation that Babs Seed was in. To avoid being bullied, she becomes the bully, possibly being forced to by Diamond Tiara herself.
While Redemption isn't foreseeable, it is possible that Silver Spoon is falling under little choice by unknown reasons to side with DT, whether it be by some sort of force, secret or perhaps insecurity because of her upper class life that she can't really be seen with "Lower Class" individuals...