I have heard of some who wanted to cover reproductions of David. There were also some cardinals who ordered the loin cloths to be added to Michelangelo's Last Judgment in the Sistine Chapel.
To me, nudity alone is not pornographic, and many on this thread nailed that. It has to excite to be pornographic. (But, of course, different people are excited by different things....let's not go there.)
Many years ago, when the show was still funny, the Simpsons did a clever bit on this subject. The statue was touring the US and some mothers objected that it was harmful to children so a fig leaf was strategically placed.
We recently had a battle about that very thing here in Richmond within the last 6 months. Seems one snotty person thought that David was "inappropriate" (repro statue in front of a mediterranean restaurant) and insisted on covering it. Finally, saner heads prevailed.