"The patients were terminally ill and could make up their own minds" is not a valid excuse for this.
Plenty of desperate people will turn to all sorts of quackery in the hopes that it will save them. That does not mean that those who push the quackery on them are in the right.
The doctors had only a hunch that maybe in some weird way it could possibly work. This is not nearly enough to scientifically justify a decision on, and ego almost certainly played a role in this.
"Isn't it better to try some idea, even if only a tenuous hypothesis?" Maybe, but there are millions upon millions of half-baked tenuous hypotheses, many of them involving magnets or quantum effects or something, and there is a process involved in pushing them from "half-baked tenuous hypotheses" to "actual possibilities that are worth experimenting on people."
There is also the issue of informed consent. It's a difficult one, because adults can make their own decisions, and that is very important, it's true. But when you're dying and some brilliant surgeon tells you he might have an experimental procedure no ones ever tried before, but he sure it will work, the balance of power starts having a tricky effect on "informed consent." Not to mention that it sounded like in this situation the patients weren't even fully understanding the details.
It's great that people try new hypotheses, but things like IRBs exist for a reason, and that's to prevent people from being experimented on without oversight and scientific backing.