Given the saga involving Dallas-based AT&T, I’ve written a lot lately about the Human Right’s Campaign’s annual Corporate Equality Index, which rates businesses according to their LGBT policies. As I’ve mentioned repeatedly, AT&T was one of 305 businesses nationwide that received a perfect score on the CEI last year. It was also one of eight North Texas-based companies to receive a perfect score, along with AMR Corp. (American Airlines), Brinker International Inc., Texas Instruments Inc., Haynes and Boone LLP, GameStop Corp., Kimberley-Clark Corp. and Sabre Holdings Inc. But North Texas also happens to be home to two companies that appear on another list yesterday from The Huffington Post — the 10 Worst Companies for LGBT Workers, according to HRC. Irving-based Exxon Mobil Corp., which again received a zero from HRC last year, is tied atop the list with the Laclede Group Inc. Meanwhile, Fort Worth-based BNSF Railway Corp., which received a 20, is in a tie for No. 4. Unfortunately, while it’s easy to avoiding spending your money at ExxonMobil, I’m not sure how you’d boycott BNSF.