Rights group LGBT Noise held a protest rally to highlight the controversy over remarks made by gay rights activist Rory O'Neill.
During the interview on RTE's 'Saturday Night Show', Mr O'Neill singled out a number of individuals and groups for their views.
"Over the past two weeks there has been a justifiable outpouring of anger and frustration in response to RTE's post-silencing of Rory O'Neill's comments," Caroline Earley of LGBT Noise said at the rally, which was attended by an estimated 2,000 people.
"Today is not just about this controversy, in a broader sense it is about defending free speech, it is about condemning censorship."
Senator David Norris, who spent last week in hospital, praised his colleague Senator Averil Power for bringing the matter to the attention of the Seanad last week and said that he wanted an end to censorship in Ireland.
He said he was outraged by reports that RTE had paid compensation to the Iona Institute following the remarks.
Last week, Ms Power, a Fianna Fail senator, called on Communications Minister Pat Rabbitte to justify RTE's decision to pay compensation to Iona Institute officials over the remarks and called the moved a "dangerous precedent".
The comments were made about John Waters, The Iona Institute and writer Breda O'Brien.