By "ad-tech" it's referring to the surveillance that underlies modern targeting of ads on the internet. YC's job ads don't do that.
When most people complain about ads, they are complaining about targeted ads.
Job postings, Show HN, and other ads on HN are contextually relevant to a majority of the users and require no tracking to present.
This post appears to be about the former, not the later.
Ads aren’t inherently fascist but the modern implementation of ads put forth by companies like meta and google are. Having terms that allow companies to spy on your daily routine and habits in order to sell that info to companies that would then push their products to you is dystopian and fascist. This is not a simple billboard. The mechanism that ad companies use infringes upon our basic rights for privacy with manufactured consent.
[1]: https://lobste.rs/