Tech mogul Elon Musk, speaking at a town hall Saturday night in Pennsylvania to support President Trump, played down the January 6 attack on the U.S. Capitol and exhorted supporters to cast votes early in the presidential swing state while describing mail ballots as a “recipe for fraud.”

The freewheeling session inside a ballroom at a hotel in downtown Lancaster touched on a dizzying range of topics, from space exploration and the Tesla cybertruck to immigration and the efficacy of psychiatric drugs. The town hall was part of Mr. Musk’s efforts through his super PAC to help boost Trump in swing states.

Mr. Musk, whom Trump has vowed to give a role in his administration if he wins next month, spent nearly two hours taking questions from town hall participants. While most were laudatory and covered a variety of topics, one was particularly pointed: A man wanted to know what Mr. Musk would say to concerns from voters that Trump’s election could lead to democracy backsliding in America considering his role in the January 6, 2021, riots at the Capitol.

While calling it a fair question, Mr. Musk also said that the January 6 attack by Trump’s supporters has been called “some sort of violent insurrection, which is simply not the case” — a response that drew applause from the crowd.

Mr. Musk also claimed that people “who say Trump is a threat to democracy are themselves a threat to democracy,” a comment that was also cheered by the crowd of several hundred people packed tightly into the ballroom. Many more watched the event on X, the social media platform Mr. Musk purchased two years ago.

Trump, he said, “did actually tell people to not be violent.” While Trump did tell the crowd on January 6 to protest “peacefully and patriotically,” he also encouraged them to “fight like hell” to stop President Biden from becoming the president.

Mr. Musk, the world’s richest man, has committed more than $70 million to boost Trump in the election and, at events on behalf of his super PAC, has encouraged supporters to embrace voting early. Still, echoing some of Trump’s misgivings about the method, Mr. Musk raised his own doubts about the process. He said that, in the future, mail ballots should not be accepted, calling them a strange anomaly that got popularized during the COVID-19 pandemic and raising the prospect of fraud.

The question about January 6 was an outlier during the back-and-forth with the crowd in which Mr. Musk was repeatedly praised as a visionary and solicited for advice and thoughts about education, arm wrestling, tax loopholes and whether he’d buy the Chicago White Sox. (He said he was a tech guy and had to pick his battles.)

Mr. Musk said he was in favor of “not heavy handed” regulation of artificial intelligence and railed against “woke religion” as “fundamentally an extinctionist religion.” He said the birth rate in America is a significant concern.

He said he believes Jesus was a real person who lived about 2,000 years ago and, when asked for the best advice he’s ever received, replied: “I recommend studying physics.”

He also called a woman to the stage to give her a large $1 million check, part of his promotion to give away $1 million a day to a voter in a swing state who has signed his super PAC’s petition backing the U.S. Constitution.

The giveaways are fine with Josh Fox, 32, a UPS driver from Dillsburg, Pennsylvania. “That’s cool,” Fox said, waiting to get into the rally earlier Saturday. “It would be nice to have it.”

Mr. Fox, who plans to vote for Trump, dismissed any suggestion the money may violate federal election rules. “It’s about driving in support and driving in people who are in support of the Constitution,” Mr. Fox said.