Too bad their definition of "spiritually weak" is flawed. To them, you need to read that damnation book and their littera-trash, attend all the boasting sessions, do much field circus, and pray to joke-hova all the time. Then you need to avoid most sex (all sex if you are gay or unmarried), materialism beyond what you absolutely need right now (good-bye, silver and gold), and most forms of spiritism. This cuts people off from what they need to become spiritually strong.
Someone who is spiritually strong, genuinely, knows where they are going. They are able to control their auras, block things out, and manipulate energy. These people do not blindly obey a group of men who may or may not even be trying to lead them to their own damnation. They see calamity and prepare, both by taking physical steps and by spiritually protecting themselves from the adverse effects. This does not come from reading that damnation book. It does not come from wasting your time pushing wastes of paper. It does not come from giving all your money into the Worldwide Damnation Fund when you need it to prepare yourself for hardships in the near future. It does not come from attending boasting sessions where being miserable is pushed.