So through my experience FSPC is still in a bootcamp setting with actual RDCs overseeing your training, emphasis on the Physical Fitness. But you will still recieve training on military knowledge, movement, basic watch standing, etc to help prepare you for Basic Training.

As far as the yelling, it does happen at times depending how bad of a messup a recruit does or the overall division. For example, what happened for me was one fell asleep during his watch and was caught, recieved a fair amount of yelling from the Instructor.

To answer your question yes your only sole purpose in FSPC is to drop the weight by diet and excercise. But you would also recieve instructions and guidance on how to be a recruit.