Modern art represents an incredibly vast span of work. A lump of metal painted yellow cannot be held as representative of all modern art. Take something like Gormley's Angel of the North, near Newcastle (UK). It's also public modern art, and mostly people have really taken to it.
Now let's imagine there were a 19th century style statue up of some PM or other bigwig insetad of Vault. Who would care? Who would walk past and think, "love the chisel work on that"? Basically, no-one. There are three plinths in Trafalgar Square in London with random Victorian types on, and they're all artistic irrelevances that no-one pays any attention to - nobody even cares who the people portrayed are any more (at least Nelson, atop his column, has the distinction of being remembered even if his statue is equally dull). That's what "inoffensive" really is: so unremarkable our views just glide off as if the art weren't even there. That is intrinsically a failure as art. Almost everything interesting is so because it draws attention. You just have to suck up the inevitability that some art will simply not be liked.
You can take this approach to architecture as well. You could be Prince Charles, who'd have the entire UK a bunch of twee cottages and neoclassical public buildings. But the Sydney Opera House, for instance, is an amazing, iconic building because it is modern art, not because someone made yet another boring, old-style stone box with Greek columns, frieze and pediment.
