It would also be interesting to have a lawyer opinion concerning this kind of orders from some judges (cantonaux / kantonale). If such a decision should be applied over all the ISPs in Switzerland, should it not be ordered (if the law permit it) by a Swiss judge and not a Vaud, nor a Zürich one ?
Unfortunatelly, I'm a techie and not a lawyer to know who can ask such things. But anyway, in the present case I think instead of willing to block traffic to the website, if it really contains contestable content, the complain should be done against the author and actions should be taken to close the website.
This would: 1) imply less third-party costs (probably it would imply more costs for the authorities to make the website closed, if it is located outside of Switzerland) 2) will achieve the ultimate target (making the content unavailable). Avoiding traffic to the offending website is just a workaround, as anybody with a little technical knowledge can use an anonymizer or a proxy to reach that content.
But my main opinion remains: I am totally against censorship. If words are offending, find the author and prosecute him. At the same time, ensure the illegal words are removed (if I am against censorship, I am not against respect of the people) without applying oversized measures such as restricting access to a whole website.