Can't see your image until approved but I received an email this week in relation to the early super hub models and a VM recommendation to change the default wi-fi passwords.
The default settings are now relatively weak by today's standards and a majority (probably) of users just leave the settings as the default.
The move by VM comes after a 'Which' article highlighted the lower level of security by leaving the original defaults as they were, hence the recommendation to change them to something more secure.
VM won't know if you have changed the password from the default but they will know you have an older device so you will have been included in the mailing list with the recommendation to change the password.
If the hub is ever reset, it will go back to the default settings as printed on the bottom of the hub, so the password would need to be updated again to a more secure version.
Also, worth noting that the settings password to log into the hub is the same for all of that particular model so that too should be changed to something more secure (although that wasn't mentioned in the email that I received).
When you refer to the process of changing the password not being secure, are you referring to logging into the router itself? That is explained at the link below
https://community.virginmedia.com/t5/Security-matters/Logging-in-to-Router-on-home-network-Insecure-...
