I think you're glossing over a major issue here: this is not merely Di Modica's attempt at imposing his vision of his work; it's also about SHE's attempt to import their vision of his work. That strikes me as being at least as objectionable.

Furthermore, works of art - like any communication - depend, in some form, on context. This is an intrinsically fuzzy area, but while it's clearly absurd to let anyone entirely dictate the context, I also feel it's questionable - misleading even - to retrospectively impose context upon them, particularly if that new context serves to misrepresent the original message, and even more so when the new message is so blatantly self-serving without being upfront about it.

Regardless of the personal meaning of art; allowing such deception encourages it, and that undermines our ability to interpret the world around us. It's hard enough without institutionalized deception.

So - fine for the statue to exist; dubious for its advertising nature to be hidden; and definitely unreasonable for it to be allowed to reinterpret others' messages so deceptively.