"It's not tenable to remain on air if your audience doesn't respect or trust you," he said.
Besides causing outrage on social media, the tweets also caught the eye of the minister, who said it was difficult to think of anything more offensive or inappropriate.
"Despicable remarks which deserve to be condemned," Mr Turnbull tweeted.
While the minister was unavailable for comment following McIntyre's sacking, his Liberal colleague Jamie Briggs applauded the decision, saying the comments went beyond being offensive.
However, some criticised SBS for firing McIntyre, including journalist Hugh Riminton, who is also a board member of Soldier On, an organisation that supports injured soldiers.
Riminton said the tweets were untimely, immature and in one case offensively wrong.
"But lest we forget, Our Diggers also died for free speech," he said.
Human rights commissioner Tim Wilson said McIntyre's freedom of speech was not being curtailed.
"We're talking about political interpretations of history and that is open for debate," Mr Wilson said.
"And he will be judged very harshly."
- AAP