Ibrahim Halawa says he took part in protests in Egypt as he had friends who were 'dying for democracy'.
The 21-year-old Dubliner was freed last autumn after four years in jail there.
He was arrested in August 2013 after taking part in a pro-democracy rally in Cairo, following the ousting of president Mohamed Morsi in a military coup.
Speaking on the Pat Kenny Show, Ibrahim denied being a member of the Muslim Brotherhood - the controversial Islamist group that played a major role during the Arab Spring.
He said: "If you ever meet one of the members of the Muslim Brotherhood, they don't deny they are Muslim Brotherhood. There's no point in me going on air and saying 'I'm not Muslim Brotherhood', and then going behind the scenes and practice as [a member of the] Muslim Brotherhood.
"I'm not Muslim Brotherhood - if anyone lives with me, they'll see how far away from a Muslim Brotherhood I am."
According to Ibrahim, he was never pro-Morsi - he was instead pro-democracy.
He explained that he felt it necessary to speak out and protest after seeing the violence in Egypt, including against his friends.
Ibrahim told Pat: "My friends, after they gave their opinion, they were shot dead - two of them were killed. [Another] died later when I was in prison.
"I had friends who were dying for democracy, so I had to say something as a human being."
He added: "I opposed the killing of an innocent human being. I am pro-democracy: if you want Morsi gone, I don't care about Morsi.
"I said 'if you want someone gone, use the ballot box - it's simple as'".
"They're thrown into prison, and tortured, and beaten"
Ibrahim acknowledged that he saw other prisoners radicalised during his time in prison, even when they were innocent to begin with.
He observed: "They went out to call for democracy, just to say 'we want to live as humans'. Then they're thrown into prison, and tortured, and beaten. Their families go through pain, and they go through pain, and their children go through pain.
"What they want to do is they want to go out and seek revenge. So people start radicalising them, and say 'OK, you want to seek revenge? This is the way to go. We have weapons, we have this.
"They're such idiots to be radicalised, because they don't have any backed-up information for getting revenge. They just want to kill for the sake of killing."
Ibrahim was on mass trial alongside almost 500 other defendants, and he noted that only around 50 of them were acquitted.
He's now determined to help others who have been falsely accused.
He explained: "There were 15 executed in Egypt two days ago, there was four executed this morning. There's a lot of innocent people who [were] given the death penalty, who could have been me, who are being executed right now.
"So I'm going to work a lot on the human rights case in Egypt."
You can listen to the full interview via the podcast below: