Because they’re all secretly Starlight Glimmers family/j

Top left: Freed from communism back in S5.  
Top: Ex-Commie Comrade Great Leader, to communist back in S5, now a good comrade teacher.  
Top right: Too capitalistic.  
Left: … no comment.  
Center: Cozy Glow’s possible future friend.  
Right: Rarity’s mom, a good capitalist supporter, unlike the top right.  
Bottom left: Another crooked capitalist which appeared before the top right one.  
Bottom: Fan-favorite to be daughter of chaos god Discord.  
Bottom right: Daughter of the top right one, after her mom appears, the CMC did the justice to free her from her mom’s abusive version of capitalism.

New head cannon!!! Diamond tiara is cookie crumbles and suri polomaree child!  
No wait, the colors don’t work

@Background Pony #CF98  
That could work too.

It’s probably just the most common coat and mane color, like how a lot of people have brown hair and brown eyes.

@icey wicey 1517  
@Goddess Erosia  
Basically what I’m thinking.
 
@PonyPon  
That too. They love their oranges and purples.

@genervt  
My Mistake. 😣

@Background Pony #4338  
Not a pony.

Wait where’s Aria Blaze?!

…

It’s a Conspiracy!

It’s called dominant color. It’s a basic principle of world/character design that says the thing you are designing will likely look more natural when a certain kind of color reigns supreme, as opposed to a huge array of dramatically different colors all in the same scene or thing you’re designing. It’s basically just saying that a certain range of colors just naturally look good together and others don’t.
 
These characters are using purple hair, because their sort of pink-ish bodies blend well with it. Pink and purple have a lot of shades that go well together.
 
I’m not here to throw stones at any individual OCs, but this is kind of what makes most people decide which OCs are actually interesting and which are stupid looking. Believe it or not, there are actually limitations on what will look good in this cartoonish world of multi-colored rainbow ponies. The first mistake people make when designing OCs is that they don’t realize that, and they make characters that somehow just look too weird even for this show. Sonic OCs did that a lot too, with extremely bright and sharp colors all over the place in an attempt to be “edgy” and “different”.

So what? I see thousands of ppl with my skin tone and hair color on a daily.

Same reason they like the orange and purple combination.

@AC97  
Starlight is a variation of purple. A lot of people get it wrong thinking shes pink.

@sharpshadow
 
She does have purple in her hair though, so does Starlight.

@AC97  
Except Twilight’s mane is blue. You can’t trust Ember.

Starlight. Is. Purple.
 

 
Why didn’t either Twilight or Starlight contradict her if they thought she was pink?
 
(For that matter, Amethyst isn’t what I’d call “pink” either, and probably others)

@icey wicey 1517  
That’s what I was about to say

Because pink and purple go well together?

Not enough, get those numbers up

Four of these are more purple than pink. You call Amethyst pink?

@Background Pony #E71A
 
it’s ok, i miss them too….