Hi Peter. I don't know a technical reason why the code wasn't changed.
This patch came in when I wasn't involved with roundup.

Full text indexers like xapian or whoosh I thought were meant
to handle this better than native.

From a process level, there are no tests associated with this
patch. Support for this needs testing on all rdbms back ends at
minimum.

Also support for anydbm should be added, or documentation updates are 
needed to explain this change.