[zdragnar]

Actually, filming entrance and exits is probably necessary for them to have insurance against theft, which probably is necessary for them to continue operating.

Further, some stores put locks on items and displays that others do not. These are also required for the store to continue offering such services.

You, as an individual, may not have undermined the store. However, you, as an individual among many, may be the reason why certain stores are not able to function as other stores do.

EDIT: to clarify my point, I don't think the GDPR takes how revenue is obtained into account. The revenue model itself must still conform to user consent. The analogy of Walmart to ad-blockers is interesting, though slightly off when one behavior is illegal and the other is not.