If anyone actually enjoys this story they have to have the worst taste ever. NTR is one of the lowest tier fetishes ever, on top of this being crack. Which is more often than not bad by default.
"If ______ actually likes __________ they're _________ to me."
Okay. I can see where your subjective opinion is coming from, but I don't understand why you would actually look down on someone who enjoys something you don't. Even if the story isn't what I'd like it to be, as a fellow artist I can appreciate the fact that someone actually put time and effort into drafting this, inking it, adding detail, and even using tones (which is, as most mangaka say, "annoying to do") properly. The art is high quality, and I can tell a lot of thought was put into maintaining the structure of the entire 34 pages, front to back. It's not just a point-A-to-point-B kind of plot.
If I were to have a chance to personally buy this doujin from the artist's table, I don't think I'd stand there and tell them off for drawing something this dark, for drawing up a plot I hated, or for just drawing Sayaka/Homura. On the creator's end, I also wouldn't particularly like being told my work is "terrible" just because I put a lot of time and effort into drawing something I wanted to draw (or translate, clean and edit, in Yuri-ism's case).
Multishpping exists, and this artist definitely ships in zigzags. We all can't have that dedication to one true couple, after all--not when there are so many more scenarios and possibilities between character A and character D!
Addressing the "out of character" remark, I'd say this was fine in itself. This Kyouko is a lot more considerate to others' thoughts and feelings, and thus would not interfere with Sayaka and Homura until Sayaka says something to indicate that she should act. Devil Homura is unnaturally deceitful and my opinion actually revolved around how she was being OOC in Rebellion itself. I thought it was odd how she did a complete 120 degree turn from her original personality, but I'm probably going off topic now---I'll stop here.