"Lack of assertiveness" in Dirtydozenweb3
 

As I was translating Dirtydozenweb3, I got stuck with this expression "lack of assertiveness."

I know that the expression talks about someone who is not able to say or act in his/her own thoughts.

However, in my point of view, assertiveness has a meaning that is rather negative, and therefore 'lack of assertiveness' seems it has a meaning that is rather positive.

Is it just me puzzled by the combination of the words, or is there a hidden meaning that I dont know of??

assertiveness can be both positive or negative, usually decided by the outcome.
lack of assertiveness in the 'dirty dozen' refers to a situation where a junior crew member perceives a problem but is unable/unwilling to express this to a senior crew member due to their perceived status. (see pan am/klm collision in tfs. or 737 potomac river)

I think that this definition of assertiveness is quite accurate.

"Demonstrating assertiveness means there's no question where you stand, no matter the topic. Cognitively, to be assertive implies a lack of anxious thoughts in light of stress. Behaviorally, assertiveness is all about asking for what you want in a manner that respects others. Assertive people don't shy away from defending their points of view or goals, or from trying to influence others. In terms of affect, assertiveness means reacting to positive and negative emotions without aggression or resorting to passivity."

The part in bold is what is referred to in the Dirty Dozen, as in the examples given by Mr.newfy.