That doesn't sound like an argument against the right to try, that sounds like an argument for requiring specific, intentionally frightening language around informed consent. The thing is, probability is a bitch, and emotionally filtered probability is the devil. An experimental treatment for a terminal illness can be 99% likely to result in a quicker or more painful death, but is it really right to deny the 1% chance to someone who understands the statistical choice in front of them?
Another facet of this is: should insurance pay for it? Or should the patient bear the financial burden when they want to try a shake-oil cure? Especially in this case when the drug is now FDA approved?