But on Monday the Republican presidential hopeful was on the receiving end of the harsh words -- with no opportunity of rebuttal -- as British MPs made their disdain for him clear during a parliamentary debate on whether to ban him from the country.
In doing so, the parliamentarians served up blunter criticisms than some of his rivals for the Republican presidential nomination have landed, labeling the 69-year-old "poisonous," "a buffoon" and even a "wazzock" -- British slang for "a stupid or annoying person."
"I don't think Donald Trump should be allowed within 1,000 miles of our shore," Jack Dromey, the Labour Party's shadow home affairs minister, told the assembled MPs.
It received more than 576,000 signatures -- more than five times the number required for MPs to consider sending the matter for debate in parliament.
But the debate was non-binding, with no vote taken at the end, and was always going to be used by MPs as an opportunity to vent their thoughts on the divisive Republican under the protection of parliamentary privilege, which legally shields them from accusations of defamation or slander.
And vent they did.
'No valid points to make'
"The person you're dealing with may be a successful businessman. He's also a buffoon and has the dangerous capability of saying the most obscene or insensitive things to attract attention," said Gavin Robinson, an MP for the Democratic Unionist Party.
Victoria Atkins, an MP for the ruling Conservative Party, said Trump's "comments regarding Muslims are wrong."
"His policy to close borders if he is elected as president is bonkers. And if he met one or two of my constituents in one of the many excellent pubs in my constituency, then they may well tell him that he is a wazzock."
Her fellow Conservative MP Tom Tugendhat said he thought Trump was "crazy" and had "no valid points to make," while Labour MP Tulip Siddiq said his "poisonous" words risked "inflaming tension between vulnerable communities."
Debate 'fueling publicity machine'
About 50 of the UK's 650 members of parliament were present for the debate. But while all but one used the forum to criticize Trump -- especially his comments on Muslims -- most felt a ban was unwise, and only risked making a martyr of the politician, and boosting his electoral prospects.
"I've heard of a number of cases where people have been excluded for incitement, for hatred," said Conservative MP Paul Scully.
"I've never heard of one for stupidity, and I'm not sure that we should be starting now."
Labour MP Paul Flynn said that the "great danger" in attacking Trump was that "we can fix on him a halo of victimhood. We give him the role of martyrdom."
Atkins remarked: "We are fueling this man's publicity machine by having this debate at all today."
British Home Secretary Theresa May already has the power to ban certain visitors -- including those deemed nonconducive to the public good for reasons such as a record of hate speech -- but such a move would appear highly unlikely.
British Prime Minister David Cameron has already said he is not in favor of a ban.
Trump business: Debate 'absurd'
Trump's camp responded to the debate via a statement from one of his companies Monday.
Sarah Malone, executive vice president of Scotland-based Trump International Golf Links labeled the debate "ridiculous" and "absurd," saying the British Parliament was setting a "dangerous precedent" and "sending a terrible message to the world."
But at least one of the MPs participating in the debate felt that the brash New Yorker was unlikely to be overly concerned about the opinions of a gathering of British MPs.
"I'm not sure that he's going to be terribly worried about this debate," said Conservative MP Sir Edward Leigh.