Donald Trump Jr. made a Holocaust joke on free video father having sex with pregnant daughterThursday, and perhaps the most surprising thing about it is that it's not that surprising.

Trump was speaking on a Philadelphia radio station on Thursday, complaining that he feels media outlets treat his father (Republican presidential nominee Donald Trump) unfairly.

“They’ve let her slide on every discrepancy, on every lie," Trump said, talking about his view of how media outlets treat Democratic presidential nominee Hillary Clinton. “If Republicans were doing that, they’d be warming up the gas chamber right now.”

The reference to gas chambers did not go unnoticed by the press, the Clinton campaign or by the Anti-Defamation League, which works to combat anti-Semitism.

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Trump Jr. later said his comment was about "corporal punishment," and it might be easier to dismiss if this were the first time Donald Trump Jr. has interacted with the world of white supremacists and neo-Nazis.

But it's not.

Just four days ago, Trump Instagrammed a photoshopped picture of himself and other prominent Trump campaign figures standing alongside Pepe the frog, an internet meme that has been commandeered by neo-Nazis and the white nationalist alt-right movement, who have made it a sort of unofficial mascot of the Trump campaign.

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Clinton recently said "you could put half of Trump's supporters into what I call the basket of deplorables," referencing what she called the "racist, sexist, homophobic" elements of his campaign.

Trump Jr. has also retweeted a white supremacist and, in March, he appeared on a conservative radio show, "Liberty Roundtable," alongside a white supremacist, James Edwards, who has praised slavery and said "interracial sex is white genocide."

Trump Jr. later said he "obviously" wouldn't have done the interview if he'd known Edwards was a white supremacist and would be on the program.

The elder Trump, too, has had similar brushes with the white supremacist movement.

The GOP candidate for president famously failed to disavow support from former Ku Klux Klan leader David Duke in a February interview with CNN's Jake Tapper. GOP vice presidential nominee Mike Pence has since refused to call Duke "deplorable."

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Trump has also retweeted a Twitter user who went by the handle @WhiteGenocideTM, though the account has since been suspended.

Though prominent members of the white nationalist alt-right movement we spoke to do not consider the senior Trump to be a true member of their movement, they haven't been shy about their support of the Republican candidate, especially when it comes to his starkly anti-immigration platform.

Donald Trump also infamously tweeted an image of Hillary Clinton many considered anti-Semitic. It included a graphic that appeared to have its origins in a white supremacist corner of the internet.

The flirtation with the alt-right's racist fringe, however, is not the first time Trump Jr. has been publicly criticized for insensitivity.

In 2012, photos emerged of Trump Jr. and his brother, Eric, posing for hunting photos alongside a dead waterbuck, elephant and other animals that the pair had presumably killed on a game hunt on a safari in Zimbabwe.

“Like all animals, elephants, buffalo, and crocodiles deserve better than to be killed and hacked apart for two young millionaires’ grisly photo opportunity,” a PETA spokesperson said at the time.

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Trump, in a move that again closely resembles his father's response to criticism, tweeted his refusal to back down.

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True to his word, Trump Jr. reportedly went on a hunting trip to Canada just last month.