@Lord Mega
Maybe. But a teacher is not always to blame for their students’ actions. It’s pretty clear Cozy Glow enrolled in the School of Friendship to accomplish her goal of draining Equestria of its magic. She was playing the long game. You can’t teach someone who doesn’t want to learn.

@GeneralKenobi75
She was still twilight’s responsibility in the first place.

@Lord Mega
I don’t think it was Celestia or Twilight’s fault that Cozy Glow was a manipulative little psychopath who saw only the power that resulted from friendship rather than what made friendship strong in the first place.

Twilight, despite her faults, ended up being a good friendship teacher in the end. The Student Six are testament to that. But the main reason they turned out well was because each of them had good hearts in the first place. Cozy Glow simply did not.

@Background Pony #05BD
HAHA YEP

@I, Da Witchfinder  
There’s a reason it has the “implied tyrant celestia” tag

This comic does a good job with context clues to why she was imprisoned. Holding a scroll, showing clear remorse; It hints that she learned something she wasn’t supposed to, something that was so critical it forced Celestia to seal her. Chilling.

@Scp-3125
 
@neo4812
 
the reason Cozy was evil was because she treated friendship like a weapon, which twilight and her friends have been doing since the beginning, the only difference is it wasn’t how they wanted it, Cozy Glow was considered evil for using their own values against them in a way that was twilights job to teach them, and it all stems from Celestia making probably the most mentally unstable pony in equestria, into her main student and making her the ruler,  
So, in conclusion, everything that goes wrong in equestria is either Celestias fault or ignorance.

@neo4812  
Psychopath, sociopaths actually can be redeemed

@Lord Mega  
cozy glow was a sociopath

@Background Pony #2DD7  
They literally turn a child to stone just because twilight failed to teach them friendship properly.

This is kind of dark, considering the finale.  
This guy wasn’t joking, he was telling us the future.

I’m surprised that no one’s added the “Hilarious in Hindsight” tag to this image yet.

@damiranc1  
and when we do see them, they are in very low numbers and small amounts of land, which she defiantly doesn’t seem to mind considering there was a whole episode about a land dispute.

@Lord Mega  
Maybe it’s ‘cause plot is centered in Equestria and around ponies? That’s why other races rarely appears.

@Prometheus labs CEO  
and a quite likely one as well, ever notice how every species in equestria except for ponies are relatively rare and not all known about?  
I wonder who writes and edits all the history books?

@Lord Mega  
That’s an even more horrifying possibility

@Prometheus labs CEO  
Heh, Celestia sure does have a lot of statues, many of them look relatively similar in groups, very likely they never did anything at all, and simply looked, “Nice”.

@neo4812  
Considering her response when twi unpetrified her face I’m guessing she wouldn’t become a repeat offender if set free

@neo4812  
also she has to be there for a reason, I wonder what her crime was?

Oh dear god who knows how many of those “statues” have gone FAR beyond the threshold of madness

@neo4812  
plays illuminati music

@neo4812  
Equestria (at least the modern one) may never know.

how did she get in that pose in the first place? she was smiling before twi unfroze her

@damiranc1  
Twi finds out that Discord is far from the only one who’s been turned into stone by Celestia.