That's a good question. Why don't they want us to know where they live? My WAS did the same thing.
Is it shame?
Who knows for sure.
If MLC is about childhood issues then perhaps it's because they are scared, confused, hurt, souls with low self esteem trying to deal with reality using the only tools they have.
In the past it's worked for them. Little do they know it's not really working. Changing everything on the outside to fix something internal isn't going to work, but they have to figure out for themselves.
They don't want us around but they don't want us all the way gone either. Sounds sort of teenagerish right?
We become a threat so to speak. They don't want us to see them like this. We know the real person, they know we know this. They do their best to mask it. Be it with anger spews, self medicating, projecting, lying, becoming control freaks or rewriting history.
They will do whatever it takes to avoid having to deal with and accept who they are and what happened to put them on this crazy journey.
Sorry for the rant To answer your question fear plays a big part IMO.
With my H, I do think some of it is because he doesn't want to feel like I am "judging" him in any way. For example, his new set of friends is much younger than him, a totally different peer group, and I am sure he thinks I will say something about it. He does occasionally drop his guard and tell me about plans or what he has done and I do my best to shut up and not say anything, though inside I am usually rolling my eyes.
We are dammed if we do, dammed if we don't. They still want us around, but push us away. They still love us, but hate what we represent. They think freedom is the answer, but still miss the family unit.
Fear is a big part of my ex. I saw so much fear when he was still living here. I felt sorry for him, but could not help him.
Ex sent me an email today asking about the Holiday schedule. He does this every Christmas. It is in our divorce decree, but he still asks.
Me: 46 H:44 Together: 25 years Married: 20 years Separated: 11-30-06 Divorced 12-21-07 OW: EA began 2005 PA began end of 2006 3 children,20, 16, 6 ex asked for forgiveness 01/16/11
Mine sent an email about presents for the kids... he really doesn't know what to get them and has to get my ok on one for s21 (new phone - will cost me more $$).
i wonder if my x even knows where the divorce decree is!!
M-20 years/BOMB 12/24/06 Moved out 3/12/07 D final 7/30/2008 finding myself again
You can copy something, but it is never like the original.
Me: 46 H:44 Together: 25 years Married: 20 years Separated: 11-30-06 Divorced 12-21-07 OW: EA began 2005 PA began end of 2006 3 children,20, 16, 6 ex asked for forgiveness 01/16/11
They do their best to mask it. Be it with anger spews, self medicating, projecting, lying, becoming control freaks or rewriting history. 
To answer your question fear plays a big part IMO.