Great question — answering as the UphillTech team:
I wrote a pull request to opencart that adds an option to disable the functionality: https://github.com/opencart/opencart/pull/7166 . Once that's merged (or if you patch your code with it), you can shut affiliate marketing off in your store settings.
Full answer by Falcon Momot: https://stackoverflow.stackexchange.com/a/54499827 (CC BY-SA 3.0).
Need it done for your business? UphillTech.
