Re: Indefensible
TRT I would strongly suggest for the good of any business you work for that you go back and learn about GDPR.
You are incorrect on many of your statements.
As mentioned, when you provided consent is of no consequence, if the data was not collected in a way that would currently be compatible with GDPR that you are required to reconfirm that consent or destroy any data you hold which is not covered by the legal basis or statutory regulatory requirements.
You might have noticed the hundreds of emails you had asking you to do this just before GDPR kicked in.
There is also no such thing as "life long consent" and never has been.