Jeffrey Steingarten is straight. Sorry to disappoint you.
I think I can guess why people would wonder. His rapier wit is reminiscent of Waldo Lydecker, Clifton Webb as the obviously gay (regardless of his obsession with Gene Tierney) cavilling theatre critic in Laura. Steingarten is married (not that that proves anything), and, yes, straight. I don't know whether I'm disappointing the curious ones, but I do know how they got to Word of Mouth in the first place. In my piece "I Love Jeffrey Steingarten" (the chaste love of one writer for another's style, I assure you) I mentioned a young writer who appeared on a panel with Steingarten and seemed to have nothing to contribute to the conversation other than the fact that he was gay (this apropos of an out-of-the-blue discourse on the semiotics of pocket squares, which was well beyond my comprehension). So in my blog post about the event, "Jeffrey Steingarten" and "gay" appeared in proximity to each other, giving me Google primacy for this particular search.
If you don't believe me that Steingarten is straight, here's an excerpt from Serious Eats:
"But it’s hard to ignore the dearth of openly gay male chefs working in restaurants today. Of all the famous chefs launched by the Food Network and Bravo, how many are openly gay men? I can name one: Ted Allen. But he’s not a restaurant chef, he’s a home chef. And you can see his confidence flounder when placed alongside a straight bulldog like Jeffrey Steingarten at the Iron Chef’s judging table. Steingarten (not a chef, but a distinguished food writer) wipes the floor with him every time, and Ted Allen’s credibility is immediately called into question. Who is this guy? What’s his pedigree? He was on Queer Eye and he has a cookbook. Big whoop."
So not only is Steingarten straight, he's a straight bulldog, one who has turned a multitude of bites into a formidable bark.