All the alternative methods require the same sacrifice. More importantly, most suggested treatments fail to cure deadly conditions or have major side effects or risks that are just as unethical to thrust upon people untested.
If you look at it properly, i.e. evaluate what should be your actions before the test (Do nothing, Impose untested treatment, Test with proper control to learn what to do with the majority of the population), the answer is rarely ambiguous.
There is a debate to be had on how much pre-clinical work to be done before clinical testing, but those are increasingly automated, cheap, and fast, so we often reach the point where a double-blind test is the next logical step.
The argument you present is based on either an unwarranted confidence in treatments, or information that wasn’t available when the decision had to be made.
