Probably because all those viewers are "face palming" and do not have a hand free to reply with an answer.
The answer is no, you do not have to unroot.
You can retain root using OTA Rootkeeper going from GB to ICS. But. if that does not hold (since all these leaks are rootable and more than likely the OTA will be) you should be able to use Razr's edge for the chance root does not hold in the upgrade.
p.s. Root is fine for the upgrade but if you have made any other modifications to the OS or have custom recovery installed the update will fail. In that case, if you are currently on 5.9.905, you will need to FXZ back to a clean stock 5.9.905. You can reroot after FXZ'ing before accepting the OTA - just do not redo any other OS modifications.