Precisely. Your name that's on your Battle.net account is used for billing purposes, used to positively identify you in case of account compromise severe enough that you cannot regain access, and a host of other reasons.
And now they want to use that as the positive identifier for you on the forums - forums which might as well be mandatory for getting technical support or customer service, as their email system takes weeks to reply and their phone lines are more often than not unable to take more callers into queue due to so many irresponsible people allowing their accounts to become compromised.
This is possibly the most insane thing Blizzard has ever attempted.