The Ukip leader insisted the UK would give Mr Trump the red carpet treatment during his state visit
Paul Nuttall said: "It does look slightly arbitrary to me, but we cannot forget he is a democratically elected president."
Mr Nuttall also said there was no question of not giving President Trump a red carpet state visit, saying there had been nothing like the level of protest when the UK welcomed leaders from China and Saudi Arabia.
An online petition aimed at blocking a full state visit by the US president has so far collected more than a million signatures.
Prime Minister Theresa May had announced the visit during her recent trip to the US.
Mr Nuttall, speaking on Monday on the campaign trail in Stoke-on-Trent Central where he is standing in the forthcoming by-election, criticised the "liberal, metropolitan hyperbole" which had greeted Trump's border move.
He said: "I will say the idea we're not going to roll out the red carpet for President Trump is nonsense.
"We did for the King of Saudi Arabia.
Gradual privatisation of the NHS has failed over many years
"We also rolled out the red carpet for the President of China, [a country] which has human rights abuses as long as your arm.
"It's another case of liberal, metropolitan hyperbole.
"(President) Obama did the same in 2013, for Iraqis."
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Mr Nuttall argued that the UK has already welcomed the leaders of China and Saudi Arabia
Mr Nuttall said while President Trump's move looked "arbitrary", "you didn't get all the liberals jumping up and down" when then President Barack Obama had passed a similar measure.
He was speaking after a keynote party speech on health in Stoke-on-Trent in Staffordshire.
During his speech, Mr Nuttall ruled out privatisation of the NHS under Ukip, admitting he had been "wrong" to support such a policy in the past.
May meets Trump: Historic first meeting in pictures
Fri, January 27, 2017
The two leaders will spend about an hour in face-to-face talks in the Oval Office, where President Trump has restored a bust of Winston Churchill removed by predecessor Barack Obama.
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President Trump Meets With British PM Theresa May At The White House
In a speech at the North Stafford Hotel, he said: "I am happy to admit I was wrong and I think it makes me a better politician for having the guts to admit I was wrong on this.
"I now want to make something crystal clear. Ukip has never and will never under my leadership enter any election calling for the privatisation of the NHS. Full stop."
He said "gradual privatisation of the NHS has failed over many years" and that every winter was now a "groundhog day" of crisis in England and Wales' hospitals.
Mr Nuttall pledged that Ukip does not and will not want try to privatise the NHS
Campaigning is well under way in the battleground Labour-held Stoke constituency, in what is widely expected to go down to a tight race between Labour's Gareth Snell and the Ukip leader.
Labour claimed Mr Nuttall had alarmed patients by previously suggesting what is called a "sell-off" of the NHS.
Mr Snell, Labour's Stoke Central by-election candidate, said: "Voters in Stoke-on-Trent will not be fooled by Ukip's desperate attempts to regain some credibility on health.
During his speech the Ukip man admitted he has been wrong about wanting a private NHS
"People here are busy fighting Tory attempts to privatise local cancer and end-of-life care services.
"The last thing they need is an MP who wants to sell off our NHS, putting patients and jobs at risk.
"I am the only candidate who would fight for local health services here in Stoke."