The male American PhD student who confessed to being an internet hoaxer masquerading as a lesbian blogger in Damascus has spoken publicly about the reasons behind his deception, saying he was motivated, in part, by his own "vanity".

Gay activists in Syria and further afield have reacted furiously to the revelation that the blog, A Gay Girl in Damascus, was written not by a 35-year-old woman kidnapped by security forces last week, but by Tom MacMaster, a married, 40-year-old American studying at Edinburgh University.

Speaking via Skype video to the Guardian, MacMaster, who is on holiday in Istanbul with his wife, expressed some contrition for the blog, which he began in February after constructing an elaborate web identity for Amina Abdallah Aral al Omari, a fictional lesbian Syrian, over more than four years.

He said: "I regret that a lot of people feel that I led them on. I regret that ... a number of people are seeing my hoax as distracting from real news, real stories about Syria and real concerns of real, actual, on-the-ground bloggers, where people will doubt their veracity."

Informed that Syria's official news agency, Sana, has leapt on the controversy, claiming the fictional blog had perpetuated "continuous fabrications and lies against Syria in term of kidnapping bloggers and activists", MacMaster said: "Yep. I regret that."

He had started the blog, he said, because he believed online posts about the Syrian and Israel-Palestinian situations would earn "some deference from obnoxious men" if written under an Arab woman's name rather than under his own, where "someone would immediately ask: why do you hate America? why do you hate freedom? This sort of thing."

He had made her a lesbian, he said, in an attempt "to develop my writing conversation skills ... It's a challenge. I liked the challenge.

"I also had the thing that I like to write, and my own vanity is ... if you want to compliment me, tell you like my writing ... That's how to make me happy."

But why had he exchanged many hundreds of emails with a woman in Canada, Sandra Bagaria, who believed herself to be having a romantic relationship with the blogger?

"I feel really guilty about that ... I got caught up in the moment and it seemed ... fun. And I feel a little like shit about that." He denied having been sexually excited by the interaction: "I don't want to go into that aspect particularly of it."

The student, who was later photographed by the Guardian at an address in Istanbul, confirming his location there, denied having ever met Jelena Lecic, a London woman whose photographs he appropriated from the internet and passed off as images of Amina.

"I found her photo on Facebook a while back and ... when I saw her photo, I was like, that is Amina ... So I just nabbed her photos and was using her."

During the course of his deception MacMaster masqueraded as "Amina" in direct communication with a number of news organisations, including the Guardian, whose correspondent in Syria had taken detailed steps, at some risk to the journalist, to meet the blogger. MacMaster had emailed the correspondent with a photograph, purportedly of Amina, which was in fact of Lecic.

Gay activists in Syria have reacted with fury to the revelation of the blogger's true identity and to the suggestion that MacMaster had written it in an attempt to help their cause.

"There are bloggers in Syria who are trying as hard as they can to report news and stories from the country," wrote Sami Hamwi, a pseudonym for the Damascus editor of GayMiddleEast.com. "We have to deal with [more] difficulties than you can imagine. What you have done has harmed many, put us all in danger, and made us worry about our LGBT [lesbian, gay, bisexual and transgender] activism. Add to that that it might have caused doubts about the authenticity of our blogs, stories, and us."

MacMaster told the Guardian: "I am not happy about that. And I understand their concern ... I don't want to put anybody at risk, or increased risk. And in actual fact, some of my self-justification was that in having a completely fictional character being bold and forward, then it makes it easier for real people. Which is probably just a self-justification, but it was something that crossed my mind."

His post last Monday, in which he posed as a cousin of the blogger claiming she had been kidnapped by Syrian security services, "was, stupidly, my sort of 'away message'", written as he and his wife left for a holiday in Istanbul, he said.

MacMaster's wife, Britta Froelicher, is studying at the University of St Andrews for a PhD in Syrian economic development. He said she had not participated in the fiction. "She is a student of that region - Syria, specifically. She is extremely knowledgeable and obviously a great consultant for such a project. But I am the sole author."

Why was the going-away message "stupid"? "I wanted to shut down the whole blog for a while, and I was thinking I would phase out the character, and having her abducted was not the way to do it." He had intended, he said, to post in a few days that Amina "had been released, had left the country and was not going to blog any more".

As questions about the identity of the mysterious blogger became more acute in the days after her supposed abduction, a number of individuals and bloggers, among them journalists from the website Electronic Intifada (EI), traced internet leads that increasingly pointed to MacMaster.

Confronted by EI and by the Washington Post, MacMaster originally denied involvement, before admitting the hoax in a confessional post on the blog on Sunday. In that post, MacMaster said his intention had been in part to expose "the often superficial coverage of the Middle East and the pervasiveness of new forms of liberal orientalism".

Wasn't there a very bitter irony, the Guardian asked, that a supposedly young Arab lesbian woman had been exposed as being the fictional creation of a heterosexual American man, and lacking an authentic voice of her own? MacMaster replied: "I am very aware the irony is 20 layers thick."

Did he accept that it was difficult to criticise the media for their coverage of the Middle East when he had lied explicitly to several news organisations? "Yeah, absolutely ... I don't feel incredibly happy with myself, you know. I wish in retrospect I would have done things very, very differently."