Vegapunks were scared for the Seraphim (who are far more durable than BM) to take lasers, Big Mom's own strongest attacks are a mimicry of lasers, Big Mom herself was shown trying to avoid taking Franky's radical beam despite ignoring everything else, G5 Luffy was gonna lose his head against Kizaru's light sword from a clone.
Stop this bs narrative already, Kizaru can spam these attacks without any tax on his stamina, Big Mom isn't eating those forever when it's been shown time and time again they are the top draw of elemental attacks even via Big Mom herself. Kizaru could press a haki god master swordsman Rayleigh in CQC, so please don't act like Kizaru can't piece Big Mom up, especially since he can ignore the hakiless homies.
It's an ungodly bad matchup for BM.