If they want to question law, they need to do that directly, perhaps?
I assume they would be able to question discrimination laws effectiveness or rightness, but just not say 'we stand against [religion of your choice] beliefs', for example?
Likewise, they could posit 'we disagree with the EA single sex exemptions' would be okay, but 'men must be allowed to access women's rape crisis services' would be dodgy.
For various reasons, but I'm just trying to look at the logic.