Well, the good news is you won't be meeting obnoxious elitists when you just start out. The bad news is you'll be meeting obnoxious people all the same, elitist or not.
I definitely think the number of obnoxious people in LoL is lower than that which I see in DotA, so don't worry. Every game has its black sheep, just learn to enjoy the game.
An easy beginner hero to learn would probably be Ashe, which you start out with in the Tutorial game. Go play the Tutorial if you haven't yet.
The Guides & Strategy forum is a great place to look for guides as well as post questions regarding gameplay. Since you're a new player, you can actually post your questions in this forum as well.
For Ashe, I'd recommend maxing Volley first, followed by Frost Arrow, picking up your ultimate (Enchanted Crystal Arrow) at level 6,11 and 16. Ashe plays a lot as a support DPS/AoE slow/general annoyance. Her Volley shot applies a slow to all enemies who are hit by them nasty arrows, slowing their movespeed for a few seconds. Her ultimate, Enchanted Crystal Arrow is a great fight initiator as well as a very good ganging tool if you get good at aiming it. (You can shoot it across the map)
Buy damage, some boots of your choice (except Berserker Greaves), and some health so you don't die immediately. Cooldown reduction also helps immensely to spam Volley more.
Don't know what else to include without this being incredibly long-winded. You should really try out the champions that are free for the week to see which one you have a good feel for. Some people like to start out with ranged champions, since that feels easier. Others like starting out with tanky champions, since they die less. It's really up to your preference, and I believe people always start out with a natural affinity for a certain champion/playstyle, and it's really up to you to discover that as you go along.
With that...happy battling and if you have any other questions feel free to keep asking (: