No matter how dumb it is, in what way is it ambiguous? How could you possibly interpret it in any other way than 'be more confident/less hesitant in taking credit'?
>>Improb+(OP)
> No matter how dumb it is, in what way is it ambiguous?
That it is unclear is obvious in that the person using the stereotype couldn't identify the concrete, actionable behavior they intended to encourage when directly questioned.