"What I would say is that Israel also knew the implications. The first time around when he posted the first time and the implications for the wider game was something the tribunal took into consideration, both financial and also reputation from a disrepute perspective, when they got to the stage where they decided termination was the only option."
Folau's April 9 Instagram post was the third such post in recent memory, with another pair in 2018.
While he copped heat at the time, Folau kept his job, even re-signing a new four-year deal.
Castle said he deserved a second chance but that RA was going to learn from their mistakes.
"I think specifically having used the words 'hell' and 'gay', and the homosexual community, in the first post, we had specific conversations about the harm that it had caused the community and the offence it has caused to that community," she said.
"To use those very same words again, to create that same issue with that same community is something I was very surprised about, because it had been very clear from what I had said that we supported his strong religious view, in fact we were proud of his strong religious view, but he needed to express those in a respectful way."
Castle did admit RA hadn't added an extra clause regarding social media as the contract was under the collective agreement and "you can't add clauses that are to the detriment of the player".
But RA did give Folau and his manager a letter as well as a face-to-face meeting which detailed expectations of him on social media.
Once he made the Instagram post, Castle said it took 36 hours to get in touch with the star, and the decision was made to chase a termination of Folau's contract.
She also admitted the entire scandal could have been overcome with the posts being taken down and an apology within the first 24 hours.
Several Polynesian players have expressed concern with Folau's situation over the last month, including Wallabies prospect Taniela Tupou, who tweeted: "Might as well sack me and all the other Pacific Islands rugby players around the world because we have the same Christian beliefs".
Castle said there will still be some work to do with the Polynesian players to explain why Folau's case is so different.
"I have spoken to a number of players myself and Scott Johnson and Michael Cheika have also spoken to players," she said. "And once they understand and it is explained to them the differentiation of what Israel did versus what they want to do, there is no issue.
"Rugby Australia for a very long time have been supportive of the multicultural nature of our game, both within our playing groups and also in our wider rugby community. And that's really important, that everyone can feel safe in that environment and express their views, be (they) religious, be race, be creed, background, different nations coming together to play rugby."
"I am very confident that our players of faith feel comfortable expressing their faith and will continue to do so, as we have seen over the last couple off weeks."
