Paudie McGahon said he finds it hard to believe that Gerry Adams was given a list of alleged sex abusers anonymously.
The Sinn Féin president has previously said he received the list through the postbox of his Belfast home and it was then passed on to the Gardaí.
Paudie McGahon, who says he was raped by an IRA member in the 1990s and subjected to a kangaroo court, says Deputy Adams' house is a "fortress".
"Gerry Adams is telling the public that he got a list of 27 people or whatever it may be anonymously delivered to his door," McGahon said.
"I find that very hard to believe.
"You could walk up to my door or your door and put a letter in, but there's no way you can walk up to Gerry Adams' front door in Belfast and hand in a letter anonymously.
"It doesn't happen. It's a fortress."