Yes, Duchamp's Fountain is safe. It was attacked by an old man with a hammer, but without success. Only some pieces of porcelain were chipped away. The porcelain seems to be of good quality.
The author of the act considers them performance art. Maybe in an act of revenge, the police wouldn't reveal his name - although we know it's Pierre Pinoncelli, as this wasn't his first act of performance art with this piece - in 1993 he peed into it (and I think he also tried hitting it with a hammer).
The act itself isn't particularly original. The fact that Duchamp disapproved of museums could be an argument, but then of course, he tried, unseccessfuly, to put Fountain in an exhibition. Is messing with other people's work bad? Using other people's works for the creation of new ones is an entire tradition. A few years ago Maurizio Cattelan stole another artist's (Paul de Reus's) entire exhibition and put it as his own (and had troubles with the police because of that), Robert Rauschenberg erased drawings by De Kooning, etc, etc...
I have no problem seeing both a piece of art and a crime in such an event. I don't see why these two should be incompatible.
There is another interesting thing about the recent art attack. The way it was described by the media. Comapre the title in USA Today: "Dada artist accused of vandalizing Duchamp piece" with the one in The Independent: "Protester tries to chip away at the reputation of Duchamp's urinal". The latter refers to the artwork as to "the urinal", without even giving its title! Fortunately, other sources of information are available: the Polish Gazeta Wyborcza writes about the object's history, Le Monde has the longest and by far the most comprehensive article, citing the perpetrator/artist ("It was going to have a miserable existance...it was better to end it using a hammer"), and even mentions a rarely mentioned fact: the urinal is not the original Fountain, but one of the eight copies (??) that were made by the artist in 1964 (!!!), since the original was "lost" in 1917.
PS. According to one commentator, the dadaists made an exhibition in the 1920's where every visitor received a hammer, thus allowing her to participate in the art...