"Whilst they are faced with a barrage of information about terrorism on the internet or through the media, all too often they feel they hit a wall of silence when it comes to discussing the issue openly in schools, universities and with the police."
why the author use "come to discussing" instead of "come to discuss"
source: 3rd paragraph in
http://uk.news.yahoo.com/politics/20080807/tpl-nine-in-ten-young-people-want-to-add-81c5b50.html
if possible, can u explain is "come to" = "go to" in the above sentence ?