@TempestShadow  
It’s not so much people are upset about that, but rather artists using characters to preach their agendas/opinions/biases.  
It’s understandably cringey, and eye-rolling sometimes if it’s something not very universal, or related to the character at all.  
Like say Twilight Sparkle saying “I vote for Trump/Obama/Hilary/Duke Nukem!” It just looks silly with fictional ponies, and OOC.
 
Not to mention, speaking from experience discussing controversial things with this artist, they’re actually quite rude to those who disagree with their art.  
a6p even basically admitted to me (in a rather rude PM) they love drawing things to upset people, (like that “zomg edge” image of Twilight burning religious books) so they’re basically just a troll. This image further illustrates that sarcastically. So frankly, they don’t even want sympathy. Just attention.

this fucking website in a nutshell  
why are ya’ll so upset about a picture of a cartoon horse with some text on it

Oh the irony

Okay!
 
…Wait.

@Zennistrad  
Well, I wasn’t really defending him actually. In fact, it’s kinda hard for me to now, after seeing him draw Twilight burning bibles & an quran book… So yeah, some opinions seem weird when expressed with ponies as your mouthpiece. It’d be like having Applejack say “Down with Bush/Obama,” or something.  
(And ironically, I was a fan of said artist to, and his cute Dinky blog… So it’s kinda disapointing to see him bash my religion.)
 
@Shadow_the_Hedgehog  
Oh I think I remember him now. :P

@Beau Skunky
 
Which would be a valid point if he didn’t seem to go out of his way to be as offensive as possible.

@Beau Skunky  
Aww… you must know him, he is very famous in this pages, especially when he trolls the mods with a pikachu.

@Shadow_the_Hedgehog  
Like who? :P

@Beau Skunky  
“Using art to mock people who are complaining about him”
 
Why that reminds me someone?

I think this artist is making fun of people complaining about him using ponies for his own opinions… (Like that lame anti-religious pic he did…)

@CaptainGame  
Can’t guarantee football player but I’ll see about doing a photoshop if that.

@CallMeAl
 
This should be the next pic, a football player with Fluttershy in his mouth captioned “Stop using ponies as mouthpieces”. I’d do it myself if I had any artistic skill whatsoever.

Mouthpieces? Like in sports?

Well, at least it’s in character for her. …Whining about anything is in character for her, really.

@Blissey1
 
I shouldn’t have laughed as hard as I did at that
 
But I did
 
When will artists start making ponies eat?

@Prof.NightJack  
she can’t help it, the artist are making her do it!

Stop eating all the ice cream.