Would giving them access to the source code even matter, other than morally speaking? Meaning, just having the code won't let them crack a phone and it won't l

Would giving them access to the source code even matter, other than morally speaking? Meaning, just having the code won't let them crack a phone and it won't let them patch the OS so that its subsequently crackable would it? When the FBI is worse than the terrorists they need to take a step back and think about the bigger picture a little bit.