As a gay man who believes America’s strength comes from its diversity, Stephen Dull is opposed to North Carolina carving the existing ban on marriage equality into the state constitution. Dull is one of a handful of corporate executives who have publicly voiced an opinion on the amendment voters will decide May 8. The corporations have been silent. Dull is the vice president for strategy and innovation at Greensboro-based VF Corp., the parent company of clothing brands including The North Face, Nautica and Lee jeans. His corporation and others in North Carolina’s influential business establishment haven’t taken a public stand on the amendment, a contrast to Starbucks and Microsoft, whose support helped sway lawmakers in Washington state before gay marriage was approved there in February.