Why people play sicilian dragon defense?

I don't see why black would want to block their DSB and weaken d5 (and d6) by playing e5 in about any Dragon position... :s

Well, I guess you meant d5. :p

He should have actually followed the DragonDorf theory altough I am not so sure about combining a respectable opening with a not so respectable one lol.

I was talking about d5 move actually, not e5, sorry.