So, I didn't read the article but if these employees didn't want to be replaced by API they could theoretically be helping the AI team find weaknesses in system and improve the system even more quickly.
Their job isn't to "identify" the shoplifting, but deal with the consequences and shoplifter after it has been identified.
So if the A.I. get's better, then they harass less innocent people, and the humans job gets better.
The employees job will be at greater risk when Walmart goes full ROBOCOP.