Maybe they just dont like him/her!
Every snake has its own character and every breed has a 'reputation', usually a false perception gained from a bad experience with an individual and passed on to others as gospel. eg scrubbys are evil, bredles are poor eaters etc etc.
This is news to Us Kali, How lucky you are! We will want some pics now please! Why dint you tell us you were at taronga? Cool stuff!
Definately want to hear more about your experiences at the zoo, no matter what animals your with!

p.s regards big constrictors growing up and eating owners, if you think about it, its not really surprising, an anaconda can take down a very large animal, as can a retic. A full grown animal aiming for a full size dinner is not unusual, even if the dinner is you.
Its not a case of the snakes attitude changing because its bigger, the snake is simply acting on instinct.
You are simply no longer a threat because the snake is so big, that leaves two options, you are nothing/ignored, or you are food!
Infact the larger a snake is, the less inclined it is to act defensively in general.
we all know little snakes bite like no tomorrow, its because they feel threatened, but you ask how many owners of large snakes if they get bitten for other than food response, youll find the numbers very small.