Yeah maybe less than half, but its super easy to get into an SR run for MC, BWL and even AQ40 long as you show up, know the fights and use consumes where needed they are cake raids. If you establish yourself with any of the regular SR teams its easy to raid naxx that way also.
No idea why people think its only GDkp… Mayeb because the really thirsty ones are always spamming chat?? I think that may be the reality. They see the spam of the gold soaker raids and think that is all there is.