I think there are two distinct but interrelated issues here. One is whether the pieces presented as "art" merit the title. The other is the question of whether public funds and public spaces should be given to shock art.
In abstract art, you have a lot of pieces that don't seem to have required any particular skill or vision to create, nor do they carry any particular message. I've been to museums with displays with titles like "Three Gray Squares" which consisted of - guess what? - three gray squares hanging on the wall. The only value I see in presenting this kind of thing as "art" is to provoke discussion of "what really is art, anyway?", which is fine as far as it goes, but frankly I find it to be a rather stale and unproductive discussion which doesn't mean anything to anyone except those who fancy themselves "artists" - many of them, only because they can put three gray squares on the wall...
The other issue is a little more tangled to me. I believe in artists' right to free expression, but I don't believe that this entails a right to receive public funding or the resources of public space. (I believe in the freedom of the press, too, but this doesn't mean I think the government has an obligation to buy me a printing press). Public resources are not infinite and should be used for projects that best serve the public interest. Saying "if you don't like it, don't look at it" is an empty reply, because it implies that some people have the right to take others' tax dollars for themselves and bully them out of public spaces with an offensive visual assault, and that the offended party has no right to object or protest (since that would be "censorship"). That, to me, is both egocentric and hypocritical. If someone has the right to express themselves by putting morally offensive imagery in my public spaces, then I have the SAME right to express myself by offending them back and setting their **** on fire. I'll make a piece of performance art out of the burning. Don't censor me!
All the same, I think this puts tough choices in the hands of the decision-makers about what to do with public resources for art. No doubt, art is valuable to a society's vitality, and part of its function is to challenge and question. I accept that I'm not going to agree with all the messages that come out of publicly-funded art. Lord knows I don't want sweet Thomas Kinkade paintings all over the place (gag). What I disagree with is a hyper-individualist culture among artists that presumes that what they have to say is worth everyone hearing just because THEY happen to want to say it - disregard of the public interest that funds them - and a corresponding sense of entitlement, that public funding and facilities are at their disposal, and that those they offend are somehow morally forbidden or wrong to voice their outrage. What's good for the goose is good for the gander.