A leading Ukip candidate for the European elections argued that feminism was responsible for a rise in the number of men carrying out mass murders, because the killers felt disenfranchised and “out of options”, it has emerged.

Carl Benjamin, a social media activist who previously tweeted “I wouldn’t even rape you” to the Labour MP Jess Phillips, argued in a now-deleted YouTube video that feminism had caused male mental health to deteriorate, prompting more mass killings.

“This is what feminism has wrought – a generation of men who do not know what to do, who are being demonised for what they are,” said Benjamin, who uses the name Sargon of Akkad on social media.

“Before your stupid social justice feminist bullshit, it didn’t happen on this scale. It’s crazy – this is a disease of the modern age,” Benjamin said in the 2014 video, recorded after the murder of six people in California that year by a 22-year-old man who said the killings were a response to women rejecting him sexually.

“You are responsible for perpetuating it, by disenfranchising these poor fucking guys who don’t have any options left,” Benjamin said.

The comments were condemned by the charity Solace Women’s Aid, which tweeted: “What does this say to the 1 in 5 women who experience sexual violence? #VAWG [violence against women and girls] is perpetuated by comments like these.”

BBC News - UKIP's Carl Benjamin not sorry for MP rape comments - misogyny lives on and calls feminism a cancer. What does this say to the 1 in 5 women who experience sexual violence? #VAWG is perpetuated by comments like thesehttps://t.co/ApiPUpHWwh — Solace Women's Aid (@SolaceWomensAid) April 21, 2019

Benjamin is second on Ukip’s regional list for MEP candidates in the south-west of England should next month’s European parliament elections take place in the UK.

He was among two candidates paraded by Ukip’s leader, Gerard Batten, at a fractious press conference last Thursday, at which Benjamin responded angrily to journalists’ questions about the tweet to Phillips, saying he was being accused of “crimes against political correctness”. Phillips has said she received 600 rape threats after Benjamin’s tweet.

In the video, framed as a response to comments about the California killings by Laci Green, a feminist YouTube activist, Benjamin insists a number of times that he does not in any way condone violence and says he believes the murderer, Elliot Rodger, was mentally ill.

But Benjamin also argues that feminism is to blame for making some men feel marginalised and “demonised in society”, and thus more likely to turn to violence.

“The question you and all of your stupid fucking feminist cultists need to be asking is, why are these men becoming misogynists in the first place? What is this feminist-run society doing to them that is causing them to go insane?” he says.

He adds: “When someone takes the option of absolute, insanely last resort, you have to wonder what kind of system is producing them. And I tell you what, Laci, it is a fucking feminist system that’s doing this.”

Rodger, who killed himself after the murders, wrote a manifesto in which he described himself as an “incel”, or “involuntary celibate” – a term popular in some anti-feminist circles to describe men rejected sexually by women.

In the video, Benjamin expresses some sympathy for the plight of such men, addressing Green directly to say: “You are not a man. You cannot possibly know what drives a man has. And when someone tells you, you say, ‘He’s a terrible person. Fuck you.’”

Ukip has been approached for comment.