Because we have personal lives, and need sleep? We do not sit on the website 24/7 waiting for moderating duties. This is a completely volunteer work force, and I personally work 45 hours a week at a hospital, and have a wife and two kids that take priority over dealing with spam here for free.
Anyway, when I went to bed at 2am I did not see any, and when I woke up at 7am there were three reported comments. I have deleted them all. You're welcome.