This is what I took from the article. The point of the exhibit isn't really relevant since it doesn't fall into an existing carve out of permitted discrimination.

I get where you're coming from, and I understand what the artist was trying to do.

But for me allowing this to go all the way to a courtroom was crossing a line. The judge and everyone else working there have important shit to do, including cases where people's actual lives are being ruined by discrimination, and they shouldn't have to waste time participating in anything like this.

There's a time and a place for artwork and protests. A courtroom is not one of them.

Also, I think it was counterproductive. If you want misogynist dickheads to change their ways, you don't do it by overcorrecting too far in the other direction. This has just made them even more passionate and even less likely to treat women fairly

From previous articles it was said that the law specifically allowed certain discrimination for some types of businesses like women's-only gyms and such. It would be quite bad news if such laws were overturned. That wasn't the one brought up but it was this one:

The museum had responded by claiming the rejection Mr Lau had felt was part of the artwork, and that the law in Tasmania allowed for discrimination if it was "designed to promote equal opportunity" for a group of people who had been historically disadvantaged.

So it was a defense of an already existing law and it failed. I doubt the individual who self-represented was trying to overturn that law, but it didn't anyways. The judge just said he couldn't see how it fit.

Also from the article:

Throughout the case, the museum's supporters, including artist Kirsha Kaechele - who created the work - had used the courtroom as a space for performance art, wearing matching navy suits and engaging in synchronised movements.

Mr Grueber said that while the behaviour of the women hadn't disrupted the hearing, it was "inappropriate, discourteous and disrespectful, and at worst contumelious and contemptuous".

Fragile-ass judge. Unsurprising. Declared it wasn't disruptive at all, but was inappropriate. Fucking lol.