Administrative user password requirements were aligned with the add-user utility (see JBEAP-2351 for more info) meaning that weak password for administrative user no longer blocks the installation process.

Following part of installation guide should be updated to reflect this change:

Create an administrative user and assign a password. The password must be at least eight characters long, with one alphabetic character, one digit, and one non-alphanumeric character. Then click Next.

"Admin User Creation" screen of https://access.stage.redhat.com/documentation/en/red-hat-jboss-enterprise-application-platform/version-7.0.beta/installation-guide/#running_the_jboss_eap_installer