Western Europe is generally more tolerant, especially of top-free bathing. Areas in public parks are specifically set aside for the purpose of CO recreation. In light of all this, you've got to believe that naturism has much to offer if its participants brave legal and physical barriers to partake. The perceived danger is that it leads the weak to sexual temptation. Naturists just want Puritanical evangelists to not make judgements that affect their lifestyle.
Offense is in the mind of the beholder, true.
Some people will tell you nothing. Some people will spell out the difference- in great detail. There is little difference in the two terms as espoused by the American Association for Nude Recreation and The Naturist Society, the US's two largest CO organizations. Americans have been arguing the point since at least the 1930s, while Europeans seem to have little problem using the terms interchangeably. Most males get erections.