Honestly, ignoring the state actor part of this, even if a bunch of local kids run up and graffiti the outside of a Walmart, I don't think we tend to regard it as a fundamental failure of Walmart's duty to secure their business, or a failure of their architects and security staff to do basic diligence or follow best practices to allow it to happen.

It's just a criminal act, of which Walmart are the victim, and it's the state's job to find and prosecute and deter that kind of thing from happening again.