Software as a whole is still on its infant stage in history. As such, everything about it is still very flimsy and unreliable, just like aircrafts and elevators were at first. Those 2 already have enough eyars of development, so their experts can now say those things and be true, but software is not only newer, but also a whole other beast to deal with.

Software has to be the single hardest thing to make safe in the world regarding products and services right now. Too abstract and lacking of law backup for it to work like physical objects 100%, so the best they can guarantee you is "yes, it will do the thing, assuming some random bored person on the internet doesn't hack you or DDoS you, in which case, good luck with that lmao".

This is why I'm against voting machines, and even more against whatever app they used in the Iowa primary. WAY too easy to tamper with. And its not like we can't process paper ballots.