I am confused. The probability of someone seeing it is irrelevant, given that the leak happened already. Is security not supposed to be preemptive? For such an easy measure to take (password changing), saying you don't want to change it seems pretty silly. You can change all of your passwords in 30 minutes tops.
I believe the CTO is also mistaken about the probability anyway. As this is more publicized the likelihood of malicious people exploiting this will only increase. Therefore it's a race between them and the good actors fixing the problem. In the interim, changing your passwords at the very least should be done.