Story highlights Errol Louis: Donald Trump's press conference turned into a tantrum over questioning by the media

He says Trump has a record of lying and the media need to double-check facts of what he says

Errol Louis is the host of "Inside City Hall," a nightly political show on NY1, a New York all-news channel. The opinions expressed in this commentary are solely those of the author.

(CNN) Donald Trump's press conference tantrum Tuesday -- during which he called one reporter "a sleaze" and lashed out at others for seeking verification of a $1 million charitable gift he claimed to have made to veterans organizations -- is the inevitable result of months of fact-twisting, distortions and outright falsehoods uttered by the candidate on a daily basis.

The truth of the matter is that reporters have very good reasons to take Trump's claims with a grain of salt -- and to ignore the name-calling, mockery and insults he uses to try and distract journalists from double-checking nearly everything he says.

Trump routinely and repeatedly says many, many things that are simply untrue. Not only were members of the press justified in skeptically asking Trump to prove he made the donations he'd boasted about, they -- we -- are especially required to verify any of the candidate's assertions, because they so often turn out to be at odds with the facts.

In the case at hand, Trump made a big deal of his claims -- announced on national television in January -- that he had raised $6 million to donate to veterans organizations, including $1 million of his own money. That turned out to be not quite true: Trump only coughed up the million on May 24 -- months after his promise -- on the same day that sharp-eyed Washington Post reporters called to find out if and when the donation had occurred.

"The press should be ashamed of itself," Trump said at his press conference . "You make me look bad."