I think the main problem with this series and the reason why people are getting so mad is precisely that it isn't simply a bad manga. Rather, it starts our rather nicely, getting people hooked on what is by all means a cute and somewhat silly love story about a gigantic lesbian mess of a high-school girl (Minami) trying to get together with her childhood friend and being repeatedly clam-jammed by that friends utter neutron-star-level denseness. But, then AFTER the reader is hooked, the story is dragged out painfully, with increasingly unbelievable reasons being made up why they can't get together and, most damagingly, the big revelation that the dense childhood friend isn't actually dense at all but just suffers from a rather ridiculous childhood trauma of rejection. To make matters worse, this trauma feels like a complete plot device, not really being foreshadowed at all and just generally not fitting the light-hearted comedy vibes of the earlier chapters.
This also means that the manga does not focus on its actual strengths. Because what it is really good at (besides the very pretty art) is creating nice sweet and comedic situations between its protagonists, showing their childhood friends dynamic in a really endearing way, whilst also garnishing this with a number of likeable side-characters. However, the shift happening when Yuzu's perspective is revealed forces the manga into the direction of exploring Yuzu's psychology instead, which just doesn't work with the premise. I think this is largely due to the author (or the publisher, who knows) wanting to continue the manga for longer but realising that you can't just repeat the dense childhood friend joke over and over again ad nauseum. And so some bogus underlying conflict was tacked on, disrupting the entire story.
A much better solution, in my opinion, would have been to stick to the original premise of Yuzu just being dense and then simply allowing them to get together halfway through the manga. The manga's strengths is in its cuteness and the character relations anyway, not the will-they-won't-they of romantic pursuit. Making them a couple and then using the remaining space to just deliver fluff mixed with a number of further comedic misunderstandings and relationship struggles would've been infinitely better I think. You could even continue to play the joke of Yuzu being dense, but just refreshing it through the new setting. E.g., Yuzu could behave in a way that seems intensely horny to Minami and makes her all flustered and confused, but Yuzu is actually just her normal oblivious self, which could lead to both comedy and relationship development.
Anyway, rant over. TLDR: Everything went downhill once we got Yuzu's perspective.