- Google adds some terms like "assisted opening knife" and "assist folding knife" so they are recognized as prohibited knife ads. Adding these terms could very well have been automated based on the terms having a strong association with other terms found alongside prohibited items.
- knife-depots' account suddenly contains X% disallowed knife ads, based on the new terms - where X is relatively large percentage. Account automatically disabled.
- Amazon and Walmart also have X% disallowed knife ads, but X is an extremely small percent of their overall number of items. Accounts remain active.
Fortunately, AdWords is one of the few Google properties where you can actually get a human on the phone and have them intervene with the automated results (though it can certainly take a lot of back and forth, in my personal experience).
In a more general sense, this is something that you constantly run in to if you have your automated systems performing any action that a user could view as punitive. I've yet to see a site that was open about automated actions being such - likely because they don't want to make it too easy to automate getting around the automated rules - but it does seem like there is a reasonable amount of explanation of the system that could diffuse these assumptions of persecution.