True that Covid can be transmitted by those who are vaccinated but with much less probability than those unvaccinated and in prticuluar with the Delta Strain.
Those who are vaccinated are taking reasonable precautions for minimising transmission while those who are not vaccinated are not.
The lack of precautionary actions which led to AIDS transmitters passing on the virus was the key legal argument leading to their conviction.
In law, it is a reasonable defence to say that one took all presonable precautions to prevent the damage. IMO Anti-vaxxers who demonstrate massless in public can't say that they took all reasonable precautions to minimise Covid transmission.
That said, those (like the Trump Congress invaders) who don't have money or assets are not suable; just liable for criminal punishment.