Is the company's personality-"harvesting" method ethical? Why, or why not?

Should people who attempt to answer the questionnaire be advised, ahead of time, that the data collected from those questionnaires will be used to improve the targeting of political messaging?
In terms of disclosure, here's what Cambridge Analytica's Privacy Policy (Links to an external site.)Links to an external site. currently includes under the header "How will we use information about you?": "The information we collect will be used in order to gain insight into the behavior of the whole population. We, or our research partners may contact you for direct marketing or research purposes." Is this disclosure sufficient? Why, or why not?
Consider the process of matching the profiles of questionnaire-takers to statistical profiles of other people who don't choose to answer such questionnaires (profiles based on "commercially or publicly available data points" about those others). Is the assessment of personalities by extrapolation ethical? Why, or why not? If you do have concerns about this practice, are they rooted in perceptions of fairness? The question of autonomy? Privacy rights? Other? (For more on "consumer database companies," see Pro Publica's "Everything We Know About What Data Brokers Know About You (Links to an external site.)Links to an external site.."