We know that Folau also had 'rights'.

He willingly chose to forgo his right to an aspect of his own free speech, so that he could get the benefit of a lucrative contract.

He had a 'right' to do that and he did that willingly.

His signature bought mutual benefits to RA and to himself personally, but there were also mutual obligations.

It's impossible to believe he signed that contract (and the one before) in ignorance and, in fact, he doesn't claim that.

It's impossible to believe he signed that contract (and the one before) under duress and, in fact, he doesn't claim that.

He chose to constrain himself for the money.

Then, for reasons unknown, he breached that agreement.

He didn't go to RA and seek to renegotiate or give them notice that he could no longer, in good conscience, be party to the contract, he just breached it.

A contract, freely signed, is essentially a formal promise.

Folau broke that promise and what makes it more egregious and more unprincipled is that now he's encouraging others to pay the price, because his free speech wasn't an issue when he signed the contract but it is now.