There is a considerable furore over Donald Trump’s retweeting of three posts by the deputy leader of Britain First, a neo-Nazi party. The posts claim to show videos of crimes committed by Muslims – the first of which has already been demonstrated to be false.

Trump’s tweets have shocked much of the British political and media establishment, and further called into question the planned state visit. And I must admit, I am slightly baffled as to why.

It is obviously major and horrifying news that the president of the United States, notionally the United Kingdom’s biggest ally, has retweeted a party whose aims are inimical to the hopes and values of the overwhelming majority of British people. However, while it is news, it is not new – nor is it surprising.

Trump’s first entry into active political life came as the most prominent advocate for birtherism – the conspiracy theory that Barack Obama, the first black president, was not a natural-born citizen, a claim he is alleged to have returned to in recent months. In 1973, Donald Trump was sued by the US Justice Department for racial discrimination in the apartment blocks he managed. While running for president, he retweeted far-right and white supremacist memes and picked up endorsements from members of the Ku Klux Klan and other racist organisations.

Since becoming president, Trump has attacked Sadiq Khan, London’s first Muslim mayor, for remarks he made about terrorism that were essentially identical to ones made by Andy Burnham, Greater Manchester’s first Scouse mayor, which went unremarked. Trump has retweeted far-right accounts in the past, and since becoming president. He referred to white supremacist marchers at Charlottesville as “very fine people”.

Expressions of racism and expressions of sympathy towards racist organisations and their supporters are not remarkable from Trump, and haven’t been for decades. They were known aspects of his behaviour when Theresa May flew halfway round the world to offer him a state visit to the United Kingdom. They were known aspects of his behaviour when commentators – too many to list here – talked up the importance of taking Trump “seriously not literally”, and claimed that he would moderate or “evolve” in office.

What is actually surprising is that none of the people involved in any of those decisions – not the Downing Street officials who have since left post or been sacked, not one of the commentators who claimed that Trump was an ordinary president, or belittled those who suggested that he might be otherwise – have shown even the faintest hint of contrition or, indeed, shown that they even understand the scale of the mistake they made.