The backlash to the Republican member of Congress who broke down in tears in her opposition to the same-sex marriage bill has included a familiar face – her nephew, who has called the lawmaker a “homophobe”.

On Thursday, Vicky Hartzler, a Republican representative from Missouri, shed tears as she urged colleagues in the US House of Representatives to vote against the Respect for Marriage Act, which forces states without marriage equality laws to recognize LGBTQ+ marriages from other states.

Hartzler’s high-profile objection to the bill, which passed the House following assent from the Senate and is now set for Joe Biden’s signature, prompted her own nephew to speak out against her in a TikTok video that has been seen more than 200,000 times.

In the video, Andrew Hartzler said his aunt was crying “because gay people like me can get married”. He added: “So despite coming out to my aunt this past February I guess she’s still just as much as a homophobe.”

Vicky Hartzler said the legislation was “misguided and dangerous” as it would threaten religious institutions opposed to marriage equality. The tenor of the bill was “submit to our ideology or be silenced”, the congresswoman claimed in her House speech.

Her nephew pointed out that religious schools still receive federal funding even if they discriminate against LGBTQ students. The 23-year-old has said he was reported for “homosexual activity” when attending Oral Roberts University, an evangelical private college in Oklahoma, and is part of a federal class-action lawsuit against the US Department of Education for funding such institutions.

The new legislation does not alter conditions for such funding and churches, mosques, synagogues and other houses of worship will not be required to perform LGBTQ marriages if it goes against their beliefs.

“It’s more like you want the power to force your religious beliefs on to everyone else, and because you don’t have that power, you feel like you’re being silenced,” Andrew Hartzler said to his aunt on his video. “But you’re not. You’re just going have to learn to coexist with all of us. And I’m sure it’s not that hard.”

Andrew Hartzler told Buzzfeed he isn’t close to his aunt, who is considered one of the most anti-gay members of Congress, and that his relationship with his conservative, religious parents has also become strained.

“It was weird to me that she was crying. I would say that,” he said. “I don’t think that was a performance. Knowing my aunt, I think those were genuine tears.

“I do feel compelled to speak out when I see this just to counter these messages. I don’t want my last name to be associated with hate. I want it to be associated with love.”

Vicky Hartzler is just the latest Republican politician to be publicly criticized by close members of their family. In October, Adam Laxalt, a Republican candidate for a closely run Senate seat in Nevada, was faced with 14 members of his family endorsing his opponent, the incumbent Democrat, Catherine Cortez Masto. Laxalt went on to lose.

In 2018, six of Republican Paul Gosar’s siblings backed his Democratic opponent in midterm elections for the far-right politician’s House of Representative district in Arizona. Gosar prevailed despite the familial acrimony.