There's no gray area here.
He's opportunistically hijacking the platform that is the opera company's viewership.
He, alone, had no right to this platform and the company is well within their rights to remove him.
As a thought exercise, (and I can scarcely believe this needs to be said) imagine he came out waving an Israeli flag.
If that last sentence got any of this crowd irritated, we might admit what this instance did for the operators of the opera company.