The ruling explicitly addressees this by talking about the scale and scope of Shopify's business in California. Read the 'express aiming' portions.

Trying to conflate a mom & pop shop vs. shopify is silly and not something that the court attempted to do.

Why is a mom and pop ceramics business violating consumer privacy laws?

Shopify is trying to avoid California having jurisdiction (to try them for privacy violations), because Shopify *knows* they're violating California consumer privacy laws.

The idea that enforcing consumer protection laws will somehow result in an explosion of frivolous lawsuits, or the death of business confidence, or will chill business development, is just a lie that companies push to fearmonger away consumer protections.