Artificial intelligence has been an indispensable tool for programmatic ad buying. But algorithms can’t always tell the difference between positive and negative sentiment — you need a human for that.

This was brought home to me in the days following Kobe Bryant’s death in January. The tragic event spurred a tidal wave of activity on social media, which triggered ads for his jersey and other memorabilia items. This came across as tacky to many consumers. One of my...