WASHINGTON — When President Trump was a candidate, he pledged his support for lesbian, gay, bisexual, transgender and queer people immediately after the mass shooting last summer at the Pulse nightclub in Orlando, Fla.

“They have been through something that nobody could ever experience,” Mr. Trump said at an event in Manchester, N.H., on June 13, 2016, delivering a hastily drafted speech that was originally intended to be about Hillary Clinton.

“Ask yourself who is really the friend of women and the L.G.B.T. community, Donald Trump with actions or Hillary Clinton with her words?” he said. “I will tell you who the better friend is, and someday I believe that will be proven out, big-league.”

Such proof did not come on Wednesday. But the president’s words were repeated with anger and frustration by a number of gay rights advocates who were angered by Mr. Trump’s abrupt decision to bar transgender people from any military job.