David McMillan's Twitter feed, @joebeef, is a collection of deadpan jokes, pictures of food and restaurant insider talk.

But his latest off-the-cuff remark has landed him in some hot water.

This is a screenshot of a tweet that has since been deleted. (Twitter)

Omar Khadr was released on bail on Thursday after spending nearly half of his 28-year life in prison. He is appealing his previous convictions of killing a U.S. soldier with a grenade in Afghanistan.

Omar Khadr smiles as he speaks to the media outside his new home, also his lawyer's home, after being granted bail in Edmonton on Thursday, May 7, 2015. (Nathan Denette/Canadian Press)

He was born in Toronto but spent much of his early life in Pakistan, and then Afghanistan. His father moved the family to Osama bin Laden's compound in Jalalabad, in Taliban-controlled eastern Afghanistan, in 1996.

McMillan told CBC News that he regrets sending the tweet through the restaurant Twitter account.

"I felt he was a victim of his father's influence [as] a child. I felt sorry for him whilst watching his press conference. I tweeted a sympathy tweet and anger at Stephen Harper I have from multiple subjects, In retrospect, I should not have done it from the restaurant Twitter account. I did not know all the details and it was based on emotion at that moment. I felt empathy and acted on it. It was a bad call," he said in an email.

Canadian pundit Ezra Levant spotted the tweet and whipped his Twitter followers into a frenzy by calling for a Joe Beef boycott.

Attn US tourists in <a href="https://twitter.com/hashtag/Montreal?src=hash">#Montreal</a>: this restaurant offers a free meal to Al Qaida who killed an American <a href="https://twitter.com/hashtag/BoycottJoeBeef?src=hash">#BoycottJoeBeef</a> <a href="https://t.co/jWYXbiHEMg">https://t.co/jWYXbiHEMg</a> —@ezralevant

What kind of restaurant would offer a free meal to Marc Lepine if he lived? These thugs. <a href="https://twitter.com/hashtag/BoycottJoeBeef?src=hash">#BoycottJoeBeef</a> <a href="https://t.co/jWYXbiHEMg">https://t.co/jWYXbiHEMg</a> —@ezralevant

McMillan on Friday morning publicly expressed regret for his controversial tweet:

Last night I made a dumb tweet about a subject I did not fully comprehend . It was based on a feeling of empathy —@joebeef