Here's my take on it. Obviously there are people who communally house ball pythons and do so quite successfully. Those are the types of keepers who Craig (skiploder) and Wes are most likely referring to (not trying to put words in either of their mouths).
Where problems arise, and why as a general guideline for new keepers, we recommend individual housing - is that there are many keepers who communally house as a financial short cut.
Their need for immediate gratification to add a new animal outweighs the financial decision to properly set up a quarantine tub, etc and they go out and they buy a new snake and just add it to the tank/enclosure that their established snake/snakes are already kept. THAT's where problems can and do often happen.
The point that both Craig and Wes are trying to make is that we can't and SHOULDN'T make sweeping generalizations, especially regurgitated generalizations.
However, I do agree that someone asking if they can house two animals together as a financial shortcut should probably be encouraged to re-think their decisions - as I do believe that a new keeper does not have the experience under their belts yet to be able to read their animals and the subtle cues that there may be a problem.
It's in the best interest of our ball pythons to HIDE their illnesses as long as they can before they start to show symptoms - survival of the fittest (drooling for example in RI's) that a newer keeper FIRST notices, whereas a more experienced keeper may notice a difference in how an animal is behaving, or "slime trails" on the tub/tank when they are doing routine maintenance that would allow them to catch a problem sooner.
So - if someone is asking can they house together, because they don't have enough money to get another enclosure, that means that they don't have enough money to properly QT a new animal, and I personally would discourage it.
Boy - I took a left turn down ramble somewhere - so I'll end it here!