Mr. Trump has strong backing from Cuban and Venezuelan exiles in South Florida, who like his stance against communism. And his campaign has heavily courted evangelical Latinos throughout the country. But no other group worries Democrats more than American-born Hispanic men, particularly those under the age 45, who polls show are highly skeptical of former Vice President Joseph R. Biden Jr.

Yet what has alienated so many older, female and suburban voters is a key part of Mr. Trump’s appeal to these men, interviews with dozens of Mexican-American men supporting Mr. Trump shows: To them, the macho allure of Mr. Trump is undeniable. He is forceful, wealthy and, most important, unapologetic. In a world where at any moment someone might be attacked for saying the wrong thing, he says the wrong thing all the time and does not bother with self-flagellation…

Other attendees at the event with Mr. Cejudo and Eric Trump spoke of watching Mr. Trump on “The Apprentice,” saying they liked his strong style, his apparent confidence in his own opinions. In interviews, they said they viewed his actions as president much in the same way: Even those they do not wholeheartedly agree with, they see as further evidence of his strength.