Of all the self-sabotaging half-assed confessions! Why phrase it in a way that implies it's someone else, to the person it is?! Con sarn it.
Cope time. Takuya knows all the manga tropes, including "crappy miscommunication that delays the rom com by 4 volumes." He recognizes what this is and he sees through it. Like a champ! The world's wussiest confession is received, the feelings are understood.
Cope #2. They manage to play it off and keep the status quo, for now. This is good, because the actual confession will be both girls at the same time and they all agree to be a throuple.