@Genki  
It’s sad that such absurd concepts as morality and the utterly strange idea that those you dislike somehow have rights are needed to keep us in line

Morality…such a funny word.  
What keeps us humans from destroying one another.

Correct, or for someone like me who gudied by logic alone it’s completely nonexistent

What morality means depends situation

@amess  
Well, that depends how you define “the truth” doesn’t it?
 
I mean, there are some things that are simply objectively factually true, and some things that aren’t. The earth exists. Pi is an irrational number. etc etc

@19-2000  
It also did feel to me that in the show they were trying to push it as it does fall in line with the sort of ideology that was presented in the episode where Mable tried to get Stan to stop lying.
 
To cut my philosophy short I figure truth is not relative, but truth lies within the context, and context is always unique. The rules never change but how any one action fits within the rules is where things get tricky.
 
So I didn’t really care for them adding that last little quote but I also think the way everyone else in the room suddenly froze with looks of uncertainty and then Stan barged through heedlessly grabbing some of the treasure and running off was a way of implying that even if they are serious about the message they realize not everyone would agree to this ideal and for fair reason.
 
Given thee above I suppose I am willing to let it slide but that doesn’t mean I am thrilled about it.
 
As for wether or not the artist of this particular piece is serious?  
I have no idea…

@Background Pony #263A  
She loves unicorns a LOT. The one from GF is one she genuinely enjoys, and if I’m correct, relates to. She draws a unicorn representation of herself named B**** Queen Unicorn.
 
The line “morality is relative” was said by Mabel (spoilers ahead) after being lied to by the unicorn while they were trying to get its hair. It kept telling her she didn’t have a pure heart, and it ate her up inside, but it turns out that unicorns are just jerks and want their hair for themselves. They make up the pure heart stuff so humans won’t bother them. Mabel was hurt and frustrated with the unicorn for making her think she was a bad person, and they ended up literally getting in a physical fight with the unicorn to get some of her hair. And that’s why Mabel said that line.
 
So that’s why I don’t think this is a joke image. The artist seemed to like both the unicorn and the quote, and the quote wasn’t a joke in the show (at least, I think it wasn’t). Maybe I’m missing something, but that’s what I got out of it.

@19-2000  
So the artist is sincere about spreading a message of moral relativism using a one-off parody character?
 
Does that sound right to you?

@Background Pony #263A  
I follow the artist on Tumblr and it doesn’t seem like a joke image to me. I may be wrong, though.

@Keith Mowz
 
@19-2000  
Besides that, the image alludes to the mouthpiece/DWM drama, so even if the pony itself didn’t count, it could be on Derpibooru as a fandom/meta post.

@Keith Mowz  
I guess that makes sense

@19-2000  
Because the pony is a clear MLP reference.

This isn’t even MLP? It’s Gravity Falls. I like the picture, but does it belong here?

“…the image is meant as a joke.”  
That may be, but it doesn’t prevent people from actually believing this gobbledygook.

Including that some things would thus be absolute?

Surely there are limits to this saying!  
My informal conclusion that there can be relativity in the higher realm of morals, but on the lower realm, relativity is much lower, one can even say there would be some constants.

@ExistenceNull  

 
were ethic not a taboo here? also you are right with this moral is a really spongy matter that can be press in any form to create a way to surive. But not everyone knows about that

@SFSLovenought  
This might look like a sincere mouthpiece image but the quote is just a reference to the GF episode she originally came from.

Honestly true, dependin on the enviroment and exposure to others enviroments, ones morals will be adapted to the world they live.  
Need to kill everyday to survive? Murder isn’t bad, it’s a daily occurence.  
Need to sleep during the day, work at night, don’t know of the diurnal rest of the world? Who the hell are these sun worshipers?  
Need to steal to eat? Not a bad thing, since it’s all you got.  
It goes against the innate logic put in our minds by society, but it is true, and will likely cause major if not world ending problems if we ever encounter a species with greatly skewed morals by our standards.

And what the hell is that supposed to mean?

Celestabellebethabelle is best pony.

Says you.