Allegations against O'Brien, made by the ex-cleric along with three serving priests, were revealed last Sunday, prompting the resignation of the UK's most senior Roman Catholic on Monday.
The former priest, who said he received unwanted attention from O'Brien when he was a 20-year-old seminarian, has now attacked Scottish Catholic leaders.
Reports last night said he was "disappointed" by the "lack of integrity" shown by the church.
He added: "There have been two sensations for me this week. One is feeling the hot breath of the media on the back of my neck and the other is sensing the cold disapproval of the church hierarchy for daring to break ranks. I feel like if they could crush me, they would."
He added that he felt that scrutiny had been focused on him instead of O'Brien in the wake of the scandal.
"I have felt very alone and there is a tendency to become reclusive when people are trying to hunt you down," he said.
He said he was shocked over claims that O'Brien's resignation was not linked to the scandal becoming public. The former priest said the only support he had been offered was a "cursory email with a couple of telephone numbers of counsellors hundreds of miles away from me".
He added: "I don't need counselling about O'Brien's unwanted behaviour to me as a young man. But I may need counselling about the trauma of speaking truth to power.
"The vacuum the church has created has allowed whimsy and speculation to distort the truth."
The former cleric also explained why the four came forward and said he feared the allegations would be swept under the carpet.
"This is about integrity," he said. "I thought it was best to let the men and women who put their hard-earned cash in the plate every Sunday know what has been happening. If you pay into something you have a right, but also a duty, to know what you are paying for. I am as sinful as the next man but this isn't about trying to own the moral high ground. I feel compassion for O'Brien, more compassion than the church is showing me, but the truth has to be available – even when that truth is hard to swallow."
He also dismissed suggestions the accusations contain an element of homophobia.
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