I see it as two possibilities:AdrianLP wrote:What calling could you have had that the current membership clerk (even if in a new ward/branch) should not be allowed to see that you had it?
1) It's a work-level issue. The more you record, the more you have to check and fix and the more effort that takes. I've seen membership records simplified. There was a time you could see every priesthood ordination performed and who did it. That's all been dropped for only recording the most recent.
2) You need to treat people for what they are, not for what they have been. If the ward was able to see someone's past callings, they might treat them differently. To use the above example, I could look at a guy's record and tell you if he came from a faithful family (every ordination right near the birthday and done by the father) or not (levels skipped, different ordinations done by different people). It was tempting to try and write some of them off and not try to activate them.