My brother, how many examples do you need? Without mentioning the 30s and 40s, look at the Tuskegee Experiment where men were given syphilis intentionally and withheld treatment to study it's spread in black populations. Or the San Francisco Operation Sea-Spray when dangerous bacterial were sprayed over the entire city to study it's effects on the population. Ethical frameworks exist to prevent people from harming others in the pursuit of data, because if they aren't prevented they will. I order to prevent this harm from being done, a clearly defined set of principles must be stated and written down so that everyone involved can have the same understanding when designing and approving studies.

Scientific study is by nature unethical because one must do unethical things in it's pursuit. We have ethical frameworks around Scientific Study for a reason, and it isn't because it was doing fine without those frameworks.