We are talking about binary computers here, there is no such thing as a "fuzzy" input or a "fuzzy" output.
The fact is that these MCPs are allowed to bypass all existing and well-functioning security barriers, and we cross our fingers and hope they won't be manipulated into giving more information than the previous security barriers would have allowed. It's a bad idea that people are running with due to the hype.
I just meant very generally that we (humans) are still struggling to make regular programs secure, we built decades worth of infrastructures (langages, protocols, networks) where security was simply not a concern and we are still reckoning with that.
Jumping head first into an entire new "paradigm" (for lack of a better word) where you can bend a clueless, yet powerful servant to do your evil bidding sounds like a recipe for... interesting times.