I've heard this argument, and am unconvinced. It;s hard to imagine that the 23 and Me test would be the direct line to mastectomy. I imagine that your doctor would run their own tests to make sure the procedure is valid, and (here, more of a hope), give some counseling.
The big danger I see is innumeracy. Having this gene triples your chances of getting Cancer X. Most folks will freak out upon hearing that, and never ask the follow-up like, 3 x 30%? or 3 x 0.001%?
And, how do those odds interact with the odds that a given test has some percentage chance of giving a false positive? This part requires FDA labeling, I would say, but how that info is used in making decisions, that's the tricky bit.