I'm personally not into Sprites too much myself and don't read a lot of them...so I may not be the best person for this question. But sprite comics are basically ways for people who can't draw to be able to do some form of fun Doujinshi ( fancomic ) and/or make the gags/story of their choice.
It's like fanfiction. If you're not claiming rights, then you should have the freedom to express the character/s ( at least online ) anyway you'd like.
I really don't think it's a huge deal. If you don't like them don't read them. Simple. And as far the fart jokes go, there are MORE then enough hand drawn comics on drunkduck and everywhere else that make just as crude if not cruder toilet humor then that. So I don't think it's very fair that bad sprite comics are the only ones getting slammed here. I think if you're going to address poor comics or fart jokes in comics, you should address the issue as a whole and not just single it down to one genre of comics. And again, if you don't like sprite comics, don't read them. No one's making you...=/
This difference is, with hand drawn comics, the artists have taken their time to actually script, lay-out, and then draw their strips, whilst the sprite kiddies do simple cut/copy/paste and then add whatever random dialogue that crosses their minds.
Simply put, one requires imagination and work, whilst the other just copies someone else's work.
And as for equating sprite "comics" to fanfiction is way off the mark. Fan fiction, when written by someone who can actually write and get into the characters they're writing for, can be good, and it allows the writer to build their skill for later works when they come to penning their own material or if they plan to pitch scripts or books for said franchises.
Granted, I've seen some horrific fan fiction in my time, but quite a lot does actually show a lot of promise. Heck, some of those fanfic writers go on to getting published or hired to write for shows. Heck, a lot of the Star Trek, Doctor Who and other franchise writers at some point in their lives wrote fanfic when they were younger.
Sprite "comics" based on Megaman/ Pokemon/ Sonic, etc, on the other hand requires no creativity, character creation, no detail, no developement; just cut/copy/paste/ ad nauseum, ad nauseum. I mean, do we really need 1001 Pokemon/ Sonic/ Megaman, etc sprite comics that bring nothing new and just clog up the comics listings and give webcomics a bad name.
Sorry if I'm venting, but I, personally, am sick to death of Pokemon/ Megaman/ Sonic strips that do nothing new. Just the same old sprites, doing the same thing panel after panel after panel, with no variation or change. It shows nothing but a lack of creativity, thought or work.
There are sprite comics out there that are total creations of their creator and writers. They don't use sprites ripped right out of popular kiddie games, nor do they simply copy and paste. They plot their work, write some witty dialogue and even create their own sprites. These comics are the execption to the mass of mass-duplicated tat that most people see as sprite comics.