We are human beings and most of us thrive on interaction. Battle chat and global chat allow us to interact with the entire community (in a limited fashion) and, I feel, are positive additions to the game. If a member of the community offends me, I can report it, ignore the user through the interface of just skip over postings I don't care for.
Last night (US) in global there was an atheism/religion exchange that went on for 10-15 minutes... not all of it was PC ... not all of it was clean and respectful but it was mildly entertaining and created a bit of insight into the personality (s), real or digital, of other players... I enjoyed it.