If you read what happened you'd know that this could never happen if they built their system with the minimum care required. Twillio is absolutely not the culprit.

I'm highly doubting Twilio is the culprit here. Sounds like Parler was just treating failures as valid authentication. Keep in mind that at the time the hackers gained access, Twilio had already suspended Parler's account, so there is little to no possibility of this being on Twilio's shoulders.