Currently the means to delete an account is via those articles and the webform.
The only other option that I know of for Information is via the info at the end of the Privacy Policy which has a spot for questions. They may allow you to do it the old way which was to send notarized documentation requesting the deletion and proving your identity as account holder.
16. What if you have a question or complaint?
If you have questions or wish to file a complaint, please e-mail us at DPO@blizzard.com or send a letter addressed to Blizzard Entertainment, One Blizzard Way, Irvine, CA 92618-3616, Attention: Data Protection Officer.
As mentioned, Blizzard Entertainment is a licensee of ESRB’s Privacy Certified Program. If you believe that we have not responded to your inquiry or your inquiry has not been satisfactorily addressed, please contact ESRB Privacy Certified at Contact ESRB Privacy Certified for feedback or questions., email privacy@esrb.org, attention: Vice President.
This Privacy Policy was last updated on October 22, 2020
If you wish
That is not exactly true. Blizzard has required ID to delete a Bnet account since the beginning and have required proof of identity for major account changes too - I listed many examples above. YOU just never ran into a situation where it was required for you.