Nextdoor Emails Ads to Non-Users

I received an email from Nextdoor, clearly a paid advertisement targeted at people who live in my town.

The person who paid for the ad is asking something fairly innocuous, trying to build their business by generating enthusiasm on Nextdoor. Fake enthusiasm, but that is the way capitalism works nowadays.

I decided to obscure the name of their business because I don't really consider them to be a bad actor in this. Nextdoor is.

I am not a user of Nextdoor.
I have never been a user of Nextdoor.
I have no account there.

However, my mother was an active user and, as I learned today, likely allowed Nextdoor to access her contacts. Nextdoor's privacy policy article about this mentions names, email addresses, phone numbers, and "other information" will be harvested from uploaded contact information. Clearly it includes the postal address as well since Nextdoor targeted a geographical ad at me.

Nextdoor is selling access to me, without any kind of relationship with me and never having provided any value to me whatsoever. Someone had an account, therefore my information is free for them to monetize and do with as they please.

This stuff mostly fades into the background. Even while drafting this post, LinkedIn sent an email of "Denton, this top CEO is answering your questions live" which is clearly also a paid email advertisement targeted at me. I pay for LinkedIn Premium, but my information is nonetheless still used to juice some additional revenue. I receive this stuff regularly enough that don't even think about it, but Nextdoor stood out.

privacy@nextdoor.com

I wrote to privacy@nextdoor.com:

Referencing https://help.nextdoor.com/s/article/Information-for-people-who-don-t-use-Nextdoor-Products, may I have a copy of the information Nextdoor has for my email address?

They responded:

We’re sorry to hear that this email was unwelcome.
 
Upon review, there is no account associated with your email address, therefore we cannot provide a copy of your information.
 
From time to time, Nextdoor receives information from third parties about non-users. In your case, we received your information from a third-party partner and used this information to invite you to join your Nextdoor Neighborhood.
 
I can confirm that we have deleted from our systems the personal information associated with the email address that you used to contact us.
 
Let me know if you have any questions.

I didn't mention anything about an email. Apparently they get enough complaints about this practice that they just assume it is so.