It's effectively a case of "I left my house unlocked and unarmed while I went on vacation. No one broke in, so I don't see the point in door locks and alarm systems."
Twitter got very VERY lucky that the worst that happened was some outages.
They moved hyper sensitive user data in a moving truck. If anything had gone wrong they would've exposed millions of peoples sensitive data.
You are supposed to wipe the servers before you move them, you shouldn't be driving servers around on the highway while they are still chock full of peoples credit card info and shit.