Why I think Jughead created the sideways' time line by SamRNLOST

I do believe that Jughead was detonated and it was at this time that this "place you all created" was formed.

The remaining LOSTIES(and a few others) were all at the site (except for Sun,Bernard and Rose) when Jack dropped the bomb into the hatch. They were all aware of what they were trying to accomplish by using the bomb--to create an existence where they never came to the island.This is why the island does not exist in the sideways' time line.

As far as the "bad" people appearing in the sideways,the LOSTIES did not sit down and plan who was going to be in their new existence, they simply wanted to erase the time spent on the island as if had never happend.

But, these people were destined to meet other regardless if it was on the island or in the real world. With Jughead they created a "world" where the island did not exist (sunk to the bottom of the Pacific Ocean) and Oceanic flight 815 never crashed. Destiny was for all of them to meet,remember,let go and move on.