The point Janet is making is that all sub-personalities, i.e. inflexibility, control, manipulation have BOTH positive and negative expressions.
For example, if you are inflexible in a particular circumstance, it may be absolutely correct for you to be so. Say someone is encouraging you to ingest something you do not care to have in your system. Of course you will be inflexible! But rightly so.
However if inflexibility is the automatic reaction for an individual and the knee jerk response to everything, then some balancing would be indicated.