The way a vocal minority are frothing at the mouth, you'd think Shiho NTR'd them or something.
Yeah the teenage girl acted like a teen by letting her emotions get the best of her and was shitty for a bit towards other characters. But she owned up to it, apologized, and has changed her ways. The other characters let bygones be bygones and so should the readers.
People celebrating this chapter being about the MCs and not the "side characters" are delusional. Shiho and Aki are just as much main characters as Himari and Yori.
Shiho and Aki are what I enjoy most about this manga. Himari and Yori are ok in small doses but they're just not nearly as interesting as Shiho and Aki.
I suspect the author feels similar based on how much of a focus Shiho's had for 2/3's the manga.