I was under the impression Shopify didn't promise anything about genuine goods to their customers, and were having to deal (haphazardly) with the same fake problems as their larger competitors. [0]

From reading back through their statements over the years it seemed to have shifted from (initial) 'we're a store platform, and take no responsibility for the content of the store' to (now) 'we have [unspecified] teams dedicated to IP infringement and fraudulent stores.'

[0] https://www.washingtonpost.com/business/2019/12/24/i-feel-ch...