"Bono believes that in order to get anything done, you have to stick your head over the parapet but when you do that, especially in a small country like Ireland, you get attacked.
"People laugh at Bono, but he doesn't care. As far as he's concerned, what he's doing is more important," Gay said.
"I find Browne's take on Bono completely negative and loony. What will come across in this interview is that Bono knows what he is talking about.
"It's one thing having access to Bill Clinton, Tony Blair, but he has to know what he's talking about, or they would blow him out the door," said Byrne.
Contacted by the Herald, Browne said he took the rock singer's political work very seriously and this was why it was "worth putting under scrutiny".
Meanwhile, another matter Bono discussed in the Meaning Of Life special – which airs on RTE1 next Tuesday at 9.30pm – was his parents' marriage.