I bet Hinoka was so confused with what Tsuku said since she still thinks they’re dating and then heard what she says after the boyfriend bit and took her words towards them “hanging out more” in a suggestive way and probably thought Tsuku had to say it like since they were in public.
So the current dumb thoughts they’re having:
Tsukushi - Hinoka doesn’t want a bc, so she must not be interested in romance, so I do t have a shot
Hinoka - why did she say that :( ———> we’re still dating she just had to “play dumb” :)