The extraordinary attack has been launched by Claus-Peter Reisch, 57 – the captain of German NGO ship Lifeline, which picked up 234 migrants in waters off Libya last month.
The destination of the rescued passengers sparked yet another dispute between European Union nations over who should accept them.
Last week, Malta gave the ship permission to dock, but only after Italy and seven other nations, in addition to Malta, pledged to each take some of the migrants.
But Mr Reisch, who claimed at least 277 people died off the coast of Malta while lifeboats were anchored on the island, slammed the behaviour of the EU over its treatment of migrants as the long-standing issue widens divides in the bloc.
He told Italian news wire ANSA: “It is shameful that the EU does more to prevent rescue efforts than to save human lives.
“Are we really discussing whether it is legitimate to save lives? If I had let those people drown, I would not be in front of a judge now.
“This is mean and it is a danger to democracy.”
The Lifeline’s captain also attacked Italy and Malta for hindering rescue efforts, accusing the bickering nations of hiding the death toll in the Mediterranean Sea.
They have increasingly been at odds with each other over who should take in hundreds of migrants rescued in the vast stretch of water over recent weeks, an issue that appears to have no immediate end in sight.
Mr Reisch, who believes around 100 migrants are dying each day in the Mediterranean, told the Malta Independent: “The curtain is being drawn over this farce, in which many people are dying, so nobody in the world can see it anymore.”
On Monday, Mr Reisch pleaded not guilty to charges that he entered Malta’s waters illegally and without proper registration.
His bail was set at €10,000 (£8.900), he was ordered to surrender his passport and to report to a police station weekly.
Mr Reisch is due to re-appear before the Maltese authorities on July 30. If convicted, he could be fined and sentenced to up to 12 months in jail.
He said: “I don’t think I have done anything unlawful. I saved 234 lives and assisted in two other rescue operations with Mission Lifeline.
“Out at sea, women, men and children are dying. I didn’t see the pictures of drowned bodies in the newspaper. I saw it with my own eyes.
“So when politicians say this should be stopped, maybe they should join us for one trip.”
Additional reporting by Maria Ortega.