I think it is less about being associated with DIC or about active development, just that DIC does have three important differences with redumper:
1. Audio CD splits and write offset detection, which is why we only accept Audio CDs with redumper
2. There is a difference in how Redumper and DIC decide to descramble or not descramble certain invalid/unexpected data sectors. This only affects "edge cases", but it is important as some discs will not match redump hashes as a result (while the dump itself is fine, just post-processing is different). This is a design decision between the two programs, and we have decided to fix upon redumper's handling of it. DIC has changed how it handles different types of invalid/unexpected sectors over time.
3. For the new drives (Mediatek-based blu-ray drives), the leadout sectors are read using a cache read. DIC's current implementation of the cache read is prone to producing a bad dump, while redumper has fixed it (which is why these new drives have become acceptable for new dumps).
For Plextor dumps, DIC remains acceptable for dumps, with the above caveats. We therefore recommend using redumper as a "first step". In an ideal world, everyone could dump with both programs for self-verification, but we cannot force all dumpers to do this.