At first I thought Tadokoro would be sad and angry at Nikaidou because, when asked about their relationship, Nikaidou denied that they are girlfriends and said they are just friends.
Then I realized that Tadokoro and Nikaidou are probably on the same wavelength when it comes to coming out... Tadokoro is prolly very happy that Nikaidou kept their relationship a secret.
This. I'm like you, I'm used to mangas were one of the girls says "NO WE'RE NOT GFS WE'RE NOT GAYS HAHA THE VERY IDEA WE'RE JUST FRIENDS!" and the other one is devastated and resentful and we're in for half a dozen chapters of angst angst angst. And I totally was like oh no, silly Nikaidou, why did you deny it, Tadokoro will be sho shad! But it turned out Tadokoro is okay with it. Welp at least it's original, haha.