Doujinshi inherently involves a degree of artistic freedom on the part of the creator. That can be a good thing or a bad thing, but you can't honestly be surprised that Yuri-ism, as a group which focuses on doujin, is gonna take a position of impartiality when it comes to things inherently dependent on artists' creative freedom such as pairings or yuri in subtext series.
For all you know, there might be genuine fans of MakotoxRikka out there. At the least, it is clear that the artist of this doujin is -- which could not consist of a reason to automatically call them a "bad fan" (of DokiDoki Precure), fyi. Although ManaRitsu is my own preference, the high degree of focus on Mana with other characters could have naturally lead this artist to come to prefer Rikka with another character. Having tried to express MakoRitsu's appeal via doujin, and Yuri-ism having picked it up for quality of art or other factors, where's the harm? All your vehement rejection and insistence that 'crack is trash' only smells of rabid and ungrateful ship fanatacism.
I thought Yuri-ism had made clear, via their policy statement and communication in comments quite a long time ago, that they had an open-minded perspective regarding shipping and appreciated recommendations for alternative pairings, so long as the content was high quality. Though it's been a while since I visited their site regularly, with posters here admitting to this degree of rudeness and close-mindedness I'm forced to wonder about the state of their commenter-base; if it has really devolved so unfortunately that people think this sort of attitude is acceptable.