Pastor James McConnell called the religion "satanic" and a "doctrine spawned in hell" during a sermon broadcast online.
On Tuesday a judge ruled his remarks were offensive but they were not grossly offensive and he was found not guilty.
The 78-year-old faced two charges - improper use of a public electronic communications network and causing a grossly offensive message to be sent by means of a public electronic communications network - after the comments made from the pulpit of his Whitewell Metropolitan Tabernacle on May 18 2014 were streamed online.
He was appearing on the BBC's Radio 5 Live discussing the case with presenter Peter Allen.
The pastor explained he called Islam "satanic" because in some occasions women who convert from Islam to Christianity are forced to give birth, lashed and then put to death.
The presenter put to the pastor that Christianity had things to be ashamed of too.
"I know that, I agree with that," replied the pastor.
He was interrupted by Mr Allen who said: "You can't condemn a whole faith".
"Hold on, hold on," replied Mr McConnell.
The presenter again said he couldn't "condemn a religion because of the excesses of some members".
"I'm away, bye bye," replied Mr McConnell.
