@Arkosya Nobody says it is "not yuri". The point is that this series is trying too hard to put an emphasis on their friendship and friendly experiences, which seems weird in the context of the alleged author's intentions. So I jokingly called it trying to write the gayest non-gay manga, lol. And since female friendship in Japanese fiction very often works according to Po's law (when the context is difficult to define without direct indication), it becomes very akward.
@Cornonthekopp I don't see anything non-platonic about feeling uncomfortable when someone tries to "steal" your best friend. Especially when you a shy person and accustomed to satisfy the need for communication with her. It's like half of the shippers don't have real-life friends and have never felt that way. On the other hand, a lot in this manga looks like a cliche from the collection "first gay love", but for some reason the author constantly stops at a decisive moment and turns to friendship route. I wouldn't even notice it, but because of her targeting manga as Yuri, it looks very strange.
I would think that she meant "yuri as emotional connections between girls", but as far as I know, such works are not officially called Yuri.