Demands for Goldsmiths University diversity officer Bahar Mustafa to be removed from her post have grown after it emerged she used inflammatory quotes on tweets including #killallwhitemen and #whitetrash.

Almost 15,000 people have now signed a petition at calling for Mustafa's removal following her plea for white men not attend an event for black and ethnic minority students at the south east London university. About 1,700 signed a similar petition supporting her.

Attempting to explain why she had tweeted offensive slogans, Mustafa said they were "in-jokes and ways that many people in the queer feminist community express ourselves. It's a way of reclaiming the power from the trauma many of us experience as queers, women, people of colour, who are on the receiving end of racism, misogyny and homophobia daily."

She admitted, however, that using the term #whitetrash on an official account was "not professional".

In a video posted online Mustafa added: "I, an ethnic minority woman, cannot be racist or sexist towards white men because racism and sexism describe structures of privilege based on race and gender and therefore women of colour and minority genders cannot be racist or sexist, since we do not stand to benefit from such a system."

Mustafa, who claims to have received racist and sexist abuse when the news surfaced, has also had plenty of support from the online community with many followers using the hashtag #supportbaharmustafa.

One Twitter user, Ella Baeker, said: "I #supportbaharmustafa because the question shouldn't be 'why were white people & men excluded?' but instead 'why are safe spaces needed?'"

However, others took an opposing view. George King wrote: "#supportbaharmustafa: one of the stupidest hashtags I've actually seen on here. Because replacing inequality with more inequality is right?"

Goldsmiths University said in a statement: "We have no involvement in [the Union's] decision-making or the programme of events that they offer."