Seems to me it's more a terminology issue than anything else. The common definition of "disease" is not "sickness with 100% mortality rate", so when everyone who gets a disease dies, the player is rightfully confused (and possibly irritated).
If the Messages said "so and so has contracted the Dark Black Uber-Disease of Certain and Painful Death", then the player would be more clear on the eventual consequences.
[ March 08, 2004, 18:15: Message edited by: Sand ]