Follow these simple steps.
1. Walk up to ANY of them and ask them if they really believe in bringing down the corporations.
2. Agree with them and make them feel confident about their answers and opinions.
3. Ask them where they buy their clothing, and this is the important part of this step, NICELY and try to sound like you really want to know.
4. When they answer "Spencer Gifts" or some similar store procede to step 5.
5. Point out the fact the spencer gifts is in fact a VERY VERY large corporation and that it makes millions of dollars every year off their purchases.  If they don't believe you then point out the simple fact that the mall they dwell in is in fact a, yup you guessed it, corporation run by "the man", or woman to be politically correct.
6. End the conversation and casually walk away with a grin on your face knowing that you just destroyed their entire philosophy on life and have, hopefully, made them realize how stupid and silly they are, and that they should accept the fact the the medieval ages are gone and that they are NOT in fact vampires and the sun is OK.
7. Now this one is optional.  Hand them a thing of suntan lotion and two plane tickets to a sunny island to help get them started on their new happy life accepting reality.
As for those who worship Satan, simply point out the fact that satan is IN FACT the angel that was closest to god, and was god's favorite.  He was cast out of heaven because of a dispute and he rules over hell, not to punish people for being bad, but to punish them for NOT loving god more then they did.
Then procede with step 7.
Hope this helps.