5 Li Hongzhi takes medicine instead of taking a chance
What confuses people the most is that Li Hongzhi doesn't allow practitioners to seek medical help but he's never followed the rule himself.
When Li Hongzhi worked at Changchun State-Owned Cereals and Oils Company, he and his daughter used to get medical services and there were a total of 73 reimbursement receipts for the purpose, among which 48 were for medical services gained by Li Hongzhi.[1]

From 1982 to1992 when Li Hongzhi worked at the Security Division of Changchun State-Owned Cereals and Oils Company, he sought medical services in a total of seven hospitals including Changchun Hospital, Changchun People's Hospital, No. 208 PLA Hospital, and Changchun Chaoyang District Hospital of Traditional Chinese Medicine. And this is the signature of Li Hongzhi on one of the reimbursement receipts.
In 1984, Li Hongzhi was hospitalized for surgery due to acute purulent appendicitis; in other words, the method of treatment by "eliminating Karma" proposed by Li Hongzhi wasn't applicable to himself and he refused to risk his own life to test the correctness of his own "eliminating Karma" theory.[2]

In-Patient Medical Records for Li Hongzhi in July 1987
Facing the questioning of practitioners, Li Hongzhi still managed to be eloquent.
"I have taught you cultivation, but that doesn't mean I am cultivating just as you are...Nothing in the Fa I've taught says that the Master must go through grueling cultivation just as cultivators do...Divine beings who save people come down to rescue them, so they can't be the same as human beings...should divine beings, who don't have karma, have to suffer even a bit? It was human beings' karma weighing them down...Divine beings who save people really can't be the same as those being saved. Say someone has fallen into a mud pit: would it make sense for him to refuse help if I offered to pull him out, and he insisted, 'You have to jump in here and be like me before I'll let you save me'? There's no such thing."[3]
Therefore, the reason why Falun Gong practitioners refuse medical help is that Falun Gong makes them lose basic ability of telling right from wrong and because they've been confused and manipulated by Li Hongzhi and his theory on "Cultivation" and they are no longer the master of themselves.
[2] People's Daily, Li Hongzhi Receives Vermiform Appendix Operation Proved by People's Hospital of Jilin Province (August 5, 1999)
[3] Li Hongzhi, Teaching the Fa at the Western U.S. International Fa Conference (February 26, 2005)