Fantasy is provides much easier escapism because it is not bound by rules, Science Fiction (SF) plays by the same hard science rules that we live by nowadays.
Need some evil enemy which you can direct all your hatred against? Well, the author says it is some "ancient evil" and that is that. SF might ask why people turn evil in the first place and what can be done about that.
Also, prophecy and destiny play a large role in Fantasy. Which of course means if you are a mere peasant, well, tough luck! SF is much more egalitarian, technology is user agnostic! (SF-Fantasy like Star Wars with all the Force mucking around is of course just Fantasy in space, ftr.)
Fantasy seems to long for a simpler time, in a way like the Middle Ages are romanticized. SF actually wants to make you understand complexity, not run away from it.
To really enjoy SF you need to have at least fundamental grasp of science to enjoy it, Fantasy is much more lenient with regard to the readers, viewers, gamers education.
Guess which Genre I favour! 