Have you ever used a piece of software that DID make guarantees about being safe?
Every software I've ever used had a "NO WARRANTY" clause of some kind in the license. Whether an open-source license or a EULA. Every single one. Except, perhaps, for public-domain software that explicitly had no license, but even "licenses" like CC0 explicitly include "Affirmer offers the Work as-is and makes no representations or warranties of any kind concerning the Work ..."
I don't know what our contract terms were for security issues, but I've certainly worked on a product where we had 5 figure penalties for any processing errors or any failures of our system to perform its actions by certain times of day. You can absolutely have these things in a contract if you pay for it, and mass market software that you pay for likely also has some implied merchantability depending on jurisdiction.
But yes things you get for free have no guarantees and there should be no expectations put in the gift giver beyond not being actively intentionally malicious.
Point. As part of a negotiated contract, some companies might indeed put in guarantees of software quality; I've never worked in the nuclear industry or any other industries where that would be required, so my perspective was a little skewed. But all mass-distributed software I've ever seen or heard of, free or not, has that "no warranty" clause, and only individual contracts are exceptions.
Also, "depending on jurisdiction" is a good point as well. I'd forgotten how often I've seen things like "Offer not valid in the state of Delaware/California/wherever" or "If you live in Tennessee, this part of the contract is preempted by state law". (All states here are pulled out of a hat and used for examples only, I'm not thinking of any real laws).
