I’m reading TV Tropes

“Many fans got rather upset when Futaba exclaims that her love for Hikari is different from Kokoro's, since Kokoro is a boy, and later Kokoro and Hikari indeed appear get ever closer as the series progresses. Fan speculation has it that Amano Kozue is not pleased that her manga had been seen by fans as a yuri manga.”

I can smell the fan rage from here.