I hope they get to tell their friends soon. It's not like they're homophobic since they reacted positively to that other sapphic couple in the earlier chapters. I guess main couple is just shyyy
Yeah, they're shy, especially Chidori. But this chapter gives a little insight into the specifics of their shyness. Assuming they came out to their friends, they'd still need to keep things from the the general public (remember how Abe-chan--half of that other sapphic couple--first referred to her relationship as "rumors" on the Tokyo trip? i.e., their friends may know but the whole school doesn't. And then there are the parents).
More importantly, if they were out to their friends, they'd need to calibrate how lovey-dovey they could be even in front of them. And, of course, they'd risk the old "Relationships are breaking up that old gang of mine" (see note) thing, too, where the friends could feel estranged because of the two of them being an overt couple.
I'm certainly not saying they're right to keep their relationship hidden, just that coming out creates certain complications even if their friends are totally OK with it.