Morally, justifying something by putting the good of mankind over an individual leads to all kinds of truly ugly nastiness.
Bullshit. As a society, we routinely engage in self-sacrificing activities for "the good of mankind". We donate our time to charities. We donate money. We even donate our very blood, which can have some serious (though rare) consequences.
It's a matter of risk perception. Donating time or money are perceived as being no risk, even though charities are very often the target of homocides and other violent attacks, and monetary donations have an obvious economic detriment for the donor. Blood drives make a big show of their safety procedures, and continuously promote the benefits that are enabled by such donations. There are no advertising campaigns for clinical trials, though.
Stories like this play on fear, promoting the idea that pharmaceutical companies are careless and cavalier about running harmful clinical trials, when the reality is that of the tens of thousands of drug trials run every year, this one is notable specifically because it had a bad outcome.
And medical testing in particular preys on those who are desperate, or financially in need already. They may not have a gun to your head, but in most cases its not like they'd be taking the drugs if they had better choices.
Also bullshit. Medical testing "preys" on mostly-healthy individuals who meet a particular set of criteria and, most importantly, can be found. That last part is often the most difficult. VERY few people go to their doctors and ask what they can do to help others, except for folks who are looking for unconventional ways to make money. Pharmaceutical researchers usually go to hospital networks and run queries against the hospital databases. Those databases are huge, and not tuned for such queries, so the queries take several months. Ultimately, there are very few qualified candidates returned, and they can be approached and asked to participate.
Unfortunately, most patients, unless they actually need a treatment, will not join a trial. They're under the impression that trials are unnecessarily risky, and usually won't try to understand the risk analysis before rejecting it. Out of a few hundred candidate subjects in the US, only a few dozen will actually participate. Those who are "desperate, or financially in need" are the ones who have enough incentive to overcome the prejudice and consider the actual risks.