With NetBeans 6.0 the download experience went through a major overhaul. We have now something we call internally The Matrix. In case you haven't seen it you can enter The Matrix here. The idea is that you can choose your preferred version of the IDE (e.g. if you are a Ruby developer you most probably don't want all the Java stuff, etc.). However we found out that about 3/4 of the people download the "ALL" version.
I would like to mention that this may not be the best option for everyone. If you choose the "ALL" option you can definitely expect a much slower startup, your IDE will take more space on your disk and your UI will contain menu items and actions you may never use. So before installing NetBeans I recommend to take a second and think which of the features you really need.
Why do we need The Matrix? We used to have four different IDEs at Sun - NetBeans, Java Studio Creator, Java Studio Enterprise and Sun Studio. We were able to strip the number down to two: NetBeans and Sun Studio (a lot of developers asked for this simplification actually). So now when you install the full bundle of NetBeans you basically get NetBeans + 2 other IDEs in one application + a part of Sun Studio! It's been an amazing engineering effort to bring all these IDEs together and provide them via NetBeans in an integrated experience - and the end result is in my opinion very good given the time there was to make this happen. The Matrix lets you make choices which of the features you really need and which you don't.
So it seems to me that NetBeans users are a bit greedy because they probably think "Well I'd better download and install everything just in case I need it. It's free anyway." Remember that once you make this decision it will also brings some disadvantages, like slower startup speed and UI which may be less optimized to what you do. A smaller bundle might be better for you. The choice is yours... take the red pill or the blue pill? :)