I think it depends on the artist and what the artist intends it to be. Some draw fat in a manner that is meant to be genuinely humorous or simply cute. Think of that episode of the Looney Tunes Show where Bugs Bunny gained weight (I’m not the only one who watched that show right?). Not everyone can relate to that side or even understand it, but it is the case with certain artists and viewers of fat art. Same goes for those into the true ‘fetishy’ side of it. It’s pretty much whatever the creator intends along with the sort of tone a viewer can assume based what is the norm for said creator. Obviously, this only applies to a certain degree. An artist can’t claim their piece is purely innocent comedy when it’s a picture of an obese, hot and bothered Rainbow Dash getting slammed in the ass by Soarin while she chugs cider down her gullet and expect people to go “Eh, sounds about right”. But fat art is a somewhat flexible medium as far as age of audience. But hey, just my two cents as another freak looking at obese horses on the internet.
 
P.S. The pic is adorbs.

@The Toaster Repair Pony  
Yeah, you’re not wrong

@Lupin Quill  
Oi, Hen can be really cute when she wants to.

@The Toaster Repair Pony  
>Perfectly safe  
>Mellowhen  

These are great.

Perfectly safe and perfectly cute  
Kind of reminds me of Mellowhen