George Ciccariello-Maher has resigned from his post at Drexel University, claiming he was the target of a year-long harassment campaign over several of his controversial tweets.

Ciccariello-Maher, known best for his “All I want for Christmas is White Genocide” tweet, which he claimed was an attempt to poke fun at the paranoid fantasy that the left wants to decrease the amount of white Americans, has stepped down from his position at Drexel University. Most recently, Ciccariello-Maher was relegated to teaching online courses, as the university was concerned for his safety when he was on campus.

In the wake of the tragedy, Ciccariello-Maher baselessly blamed the Las Vegas concert massacre on “white supremacist patriarchy” in October this year.

“White people and men are told that they are entitled to everything. This is what happens when they don’t get what they want,” he tweeted.

In November, he blamed the Texas church shooting on “whiteness,” claiming “whiteness is a structure of privilege and it’s a structure of power, and a structure that, when it feels threatened, you know, lashes out.”

Ciccariello-Maher announced his resignation this week via social media. He blamed “a year of harassment by right-wing, white supremacist media outlets, and Internet mobs” in addition to supposed death threats against him and his family.

“This is not a decision I take lightly; however, after nearly a year of harassment by right-wing, white supremacist media outlets and Internet mobs, after death threats and threats of violence directed against me and my family, my situation has become unsustainable,” Ciccariello-Maher wrote. “Staying at Drexel in the eye of this storm has become detrimental to my own writing, speaking, and organizing.”