This type of comment is unfortunately very common from immature girls and from some members of society who are ignorant. As 50 percent of men have balding at sometime in their lives, clearly the concept that a disease goes hand-in-hand with balding is ridiculous. History has shown us that these prejudices were common in the past.
Prior to the 20th century, tuberculous ran rampant in city dwellers and men and women with tuberculous lost their hair because of the disease and malnutrition. In those days, women would stay away from balding men because they thought they would not live long enough to support a family. Now that tuberculous is not a problem in Western cities, this prejudice is no longer the basis of a persistent prejudice. We also clearly know from polls taken in presidential elections since Eisenhower was president, no balding president has been elected since the 1950s (except for Donald Trump who almost certainly wears a wig). So this prejudice is unfortunately innate to our culture.