I get the vibe that the author somewhat regrets the fun-van event, or at least the intensity of Kanae's involvement.
The manga became way more contemplative especially after the hiatus, and the evidence of author's h-manga origins, like fanservice has all but disappeared. The van scene now feels so out of place that it's like it happened in a totally different manga (it was in fact almost totally lifted from one of her h-doujins). I think people mostly hate Kanae due to her initially one-dimensional charactization, which probably came from the author still being in tourture porn-mode lol.
Again, as a Kanae stan, I must commend her for continuing to try and improve herself, and Tomiko continues to win the awesome friend award lol.
Anyway, I very much suspect Riko being behind the mystery spam account, just because of Tomiko's reaction.
If Tomiko were to betray Kanae, Riko is pretty much the only cause I could think of.