As an exercise I once went through the process of manually requesting my information removed from most of the top brokers.
It would be difficult to automate because the opt-out processes usually aren't straightforward like unsubscribing from an email list. Many sites make it purposely difficult and involve going through multiple steps, providing verification like a drivers license, and email confirmations.
They key is to only submit information that they already have, not anything new. For documents that need to be uploaded in some cases, the options are either to use a heavily redacted real document with everything blacked out except for the essential info, or just upload a random file because most of the time no one checks and it is just a required field to submit a form.
You are correct it is not actually "deleted", but it will stop your information from showing up on the website.
And if your information is truely deleted, then when they come across your information again, they'll have no record of you, so they'll just fill in the missing gaps.
For them not to share your information, they need to know what information not to share.
Any online process that endeavors to be secure will be indistinguishable from a malicious system that tries to make your task purposefully difficult.
I just got refused by a govt site recently because of the six different forms to info they wanted in order to sign in again, one of them wasn't accepted. Namely my cell phone number was prepaid which apparently isn't acceptable anymore. So now I need to mail in forms and wait for return mail taking weeks.
I also tried to do this manually using the same resources from Bazzell and eventually just got tired of dealing with it and paid for Deleteme. To their credit, they did a pretty solid job removing my public data from data broker sites.
It would be difficult to automate because the opt-out processes usually aren't straightforward like unsubscribing from an email list. Many sites make it purposely difficult and involve going through multiple steps, providing verification like a drivers license, and email confirmations.
Here is a really good check list of different brokers: https://inteltechniques.com/data/workbook.pdf