It's not a conscious movement. First they play the game, feel interested about magic and all thos symbols, search the internet for related stuff, find occultic sites by people who say magic is good, tolerant and open-minded, try some little things for themselves, are not really sure if they worked or not but keep on doing it until they are complete believers. Truly, RPGs are not the only possible source (there are computer games, TV series, films, comics). None of those is evil in itself, and watching or playing them will not cause any harm per se. But it is undeniable that pre-teenagers and teenagers nowadays find witchcraft and neo-paganism highly appealing, and many are all too willing to let go of reason to dwell in the fantastic and cool world of 'magick'.