Someone you probably have never heard of has managed to scare virtually all of corporate America — and Wall Street is creating a new cottage industry around the fear.

Robby Starbuck, a former music television director, has turned his social media account into a weapon against corporate D.E.I. efforts, whipping up frenzy, threatening boycotts and flooding companies with negative media mentions over their diversity, equity and inclusion efforts. Tractor Supply pared back from its D.E.I. initiative in June after Starbuck tweeted that it was “time to expose” the home improvement chain. John Deere followed suit in July and Harley Davidson in August, both times following public pressure from Starbuck.

Now, Wall Street law firms and communications outfits are building businesses around preparing companies for a Starbuck offense. The methods mirror how they would prepare for a cybersecurity attack: conducting vulnerability assessments, compiling research reports and writing plans for what to do if Starbuck comes calling.

The furious scrutiny gets at the heart of a question facing corporate America: After many companies adopted and heralded their efforts to improve diversity, equity and inclusion — often citing studies showing benefits for business — they’re now grappling with how to handle a backlash when both customers and executives are split over the policies.

Their investors are not in agreement either: The New York City comptroller’s office, which oversees the powerful New York State employees’ pension fund, is already threatening lawsuits if executives concede too much.

“As a company, you might be between a rock and a hard place,” said Kai Liekefett, who co-chairs the corporate defense practice at the law firm Sidley Austin. “You have an anti-D.E.I. activist clashing with a D.E.I. activist. And you are just basically just a battleground for the culture wars that are playing out in corporate America.”