Okay, straight forward. There is security code today. And there are people who work hard to break it. There will always be someone who can use vulnerable points to beat a security system. All we saw was Tarka (who has been touted as the smartest man of his time) upload code he wrote to a computer system. Sure, we can assume that Zora is smarter than Tarka, but with the same evidence at hand, we can assume Tarka is smarter than Zora.

At a certain point, security of anything (much less a starship) will always have weaknesses if they are to be used often. Tarka wrote a better code and found away around the system. Sure, it may feel like a lazy plot point, but in the universe of space mushroom flying, this plot point is way more realistic.