Tell me guys, if you were going through an old text such as the bible, obviously you would be religious especially if you were trying to interpret it, And it just happens that your own interpretation has found out a number that could possibly mean the end of days.
Would you guys tell anyone? You are religious in this hypothetical question.
In my view if anyone finds a number to what they think is going to be the end of days, It would probably be a good idea to share it, especially in this question where you are religious and you are obligated into saving lives.
Doomsdaysayers probably do know the consequence, but they tell people anyways, but what if it actually does happen that time and the guy decides to keep the info for himself? He's going straight to hell, and we would all be pretty pissed if we found out in some other random afterlife that a guy knew of the end of days, but decided to say nothing. It makes sense to not create havoc, but were ALL going to die, I think we would deserve to know.
My guess is that some of these doomsday dates were people pulling a huge prank. Like that guy who made that Scroll and it was of a language not know, because it didn't exist and it was done using a peice of paper with three hole cut into it then layed over a huge peice of paper with a bunch of characters over it and if done correctly you have yourself a fake necronomicon that you can sell.