Delurking to add my theories:
The electromagnetic field is a natural feature of the island. It was held in check/vented/not as strong/whatever naturally for years (obviously it hasn't been sucking in planes for the last 75 years; someone would have noticed. And there couldn't have always been a handy computer to vent the charge every 108 minutes.)
Then Dharmatel shows up on the island and sets up their base. Whether they chose the island because of the weird electromagnetic properties or it was just a coincidence, I don't know. And then comes The Incident. Whatever happened in The Incident caused the electromagnetic field to get all out of whack and become extremely dangerous. They manage to jury-rig a system to keep the electromagnetism in check, pack up their toys and leave the island, leaving two schmucks in the Swan station to keep the island from imploding (and taking the world with it?) And, presumably, two even bigger schmucks in the Pearl station to watch the other guys push the button and write diaries about it that no one will read. (Why? Don't know. Maybe since they had to scrap the rest of the project, they wanted to get *some* research out of it. Obviously they think the project is still going on, since they keep sending food.)
As to the Others: this is one mystery I'd really like solved now. I'm fine with the whole exploring the island/what are the hatches for/Dharma mystery. But I'm tired of the Other's whole "mysterious unbeatable foe who aren't what they seem" schtick. I'd like to find out what their deal is, and maybe see a storyline in which the castaways and the Others are faced with a mutual threat and have to cooperate to survive.
As to why everyone is so stupid: They were all dropped on their head as infants. Every single one. That's why the island chose them--it needed a plane full of developmentally disabled pretty people for some nefarious reason.
Seriously, it's the only way I can watch the show--by constantly telling myself that all the main characters are high-functioning EMD. It works well for Stargate Atlantis, too.
As to the alcohol: Is anyone else highly amused that apparently the Dharmatel supply guys believe that good ol' Dharma brand rotgut is an essential item for their supply drops?