The Article you posted says that:
"Considerations if an uninstall password is in place
If you set a password for client uninstallation, you cannot uninstall the client silently. Clients with an uninstall password are prompted for the password, which must be entered manually. To uninstall the client silently, disable the password."
How would you disable the password?
The orignal post had a way to uninstall it without needing to provide the password. Please see:
https://www-secure.symantec.com/connect/forums/silent-uninstall-symantec-end-point-agent-without-supplying-password-1