Body Modification has been around for thousands of years and people still act surprised and shocked about it, that's exactly what I call ignorance and not having enough knowledge of History. Body modification is a complex word and has to be dissected in order to understand what involves. Some people find a navel piercing shockingly offensive while others find a full body tattoo appealing.
People are used to be told what to do and what not to do with their bodies since they're born and only a few stand out from the crowd to claim they're independence, this can be done in many ways and usually have some kind of body modification.
Society tends to criticize (in most cases) those who are modified and it is understandable that sometimes people want to live a life they call "normal" just because they want to control or be in charge of others by preventing them from living as they wish (while respecting the laws and living according to it). People will always look for something to talk about no matter if you do your best to do as they say and live the way they want you to live, they will always find something wrong, etc.
Those who are willing to break free and live their life able to express their identities don't carry that unnecessary baggage on their shoulders of worrying what people would say and don't live ashamed to show who they are. Regardless if it is a piercing, full body tattoo or having their body extremely modified.