Wow I'm not sure if everybody acting like their all ticked off are just trolling or being serious. Frankly so far so good, and where it is written that a story has to end with romance in order to be good?
The story is still going to end with romance, though? This was simply done to artifically draw the resolution out for longer, not to get to a different ending.
I'm very serious about it ruining the manga for me - this trope, along with misunderstood confessions ("I love you and want to spend the rest of my life with you!" "Wow, she really loves me as a friend, huh"), interrupted confessions (phone calls, people barging in), etc. - all of these plot devices have been used a thousand times by yuri mangaka and I'm absolutely sick of seeing them.
That's not to say that all tropes are inherently bad (this manga was very heavy on them in all regards, but I didn't mind). But this particular trope serves no positive value to the story. It's just a hacky way of delaying the climax when the author is too bad at writing to think of a legitimate way to extend the story that feels natural. And that's really the problem - it's very, very unnatural. It breaks suspension of disbelief and just feels so fake.
I've read some 2000 pages of the Adachi and Shimamura light novel, and it took a very, very long time to get to a confession. But I was fine with that because the story felt real the entire time. The author handled the long build-up to a confession in a very relateable way that felt like it could happen in real life the entire time. But this trope of girls blurting out "I have something important to tell you... I really want to be friends!!!" in a romantic atmosphere doesn't have one iota of believability to it. You can tell the author chose to write this dialogue because they didn't have any ideas for how to continue, not because it was the natural way for dialogue to flow, not because it was the best way to continue the narrative.