Why can't I delete the mac.com, icloud.com, and me.com aliases associated with my Apple ID?

I've had a simple, first initial/last name mac.com email address that has been my Apple ID login for over 20 years. My account is locked daily - sometimes hourly - due to multiple login attempts, whether by human error or automated attempts to access my account.

I changed the email address associated with my account to something completely obscure (and less likely to be mistakenly entered by a human or generated by a bot seeking access) with a third party email provider.

Apple's article located here https://support.apple.com/en-us/HT201771 states "You can't sign in to iCloud.com with an email alias. Sign in with your @icloud.com email address or the Apple ID that you use with your iCloud account."

There are three email aliases associated with my account. A mac.com version, and one for icloud.com and me.com. I am unable to delete these aliases. The statement above says plainly that you cannot sign in to iCloud with an alias. However - my account was locked - AGAIN - for 'Security Reasons', AFTER I changed the login to a more obscure address. It follows that while it is impossible to log in using an alias, it is possible to have your account locked if multiple login attempts are made USING one of those aliases.

This makes ZERO sense. The policy already equated to locking out everyone who lives in the house just because someone knocked on the door three times. It now equates to locking everyone out even though the house has now moved to a different location, is now invisible, and the knocker is still knocking at the previous address.

Side Note - as I was typing this, my account was locked again.