Short stories are a tough market. Few people can make a living writing fiction, and almost nobody can make a living selling short stories. (I've been told this was not the case 50 years ago.) There's a good percentage of professional fiction writers who stay away from short stories, not because it isn't a nice form, but because it won't pay the bills.
If for some reason you must write sci-fi/fantasy short stories, you should submit to the Writers of the Future contest. Great prizes, no entry fee, and you won't be competing against anyone who has already sold 2 or more stories. Write 4 stories per year and submit them to each quarter's contest. And stomp on a few cans while you write.
I wasn't aware of any scientology connection (aside from the contest founder) until after I won it and my wife & I were at the week-long all-paid workshop in LA. One of the best experiences of my life. They try to maintain a wall between any scientology and the science-fiction contest. None of the judges or teachers, to my knowledge, are scientologists. If you ask the judges, people like Orson Scott Card and Gregory Benford, they'll tell you what a great opportunity it is. The 15 winners I met at the workshop weren't scientologists either. Fun people, great writers.
The people I met who ran the contest were scientologists, and they were very nice people. Hubbard put the money up for the contest as a payback for his early sci-fi career. I also wouldn't turn down a Nobel prize because Nobel invented dynamite and was an armaments manufacturer.