Is it important for cultures to protect themselves from outside media influence?

Um.
In my opinion, you should protect some of your culture from things, but maybe not everything. If you want to listen to Eminem or watch the Simpsons, then go ahead and do it. If you want to watch American news, go ahead, but don't forget about your own country/culture. You don't need to go and listen to Nickelback or Justin Bieber but at least watch the news from your own country. Find out about all the interesting things going on in Canada. :)
and k if you're from somewhere where women "aren't" supposed to be showing off their bodies.. I think you should wear something that makes you feel good, but don't go wearing a crop top and short-shorts. I think you should be influenced by outside media, but have respect from your own culture still.