Politics may be the root cause, but underlying the carnage in health-care stocks is a lesson investors seem to learn over and over: that too much love can be a bad thing.

“It tends to be a popular topic as you get to election season because it’s one of the pinpoints in everybody’s financial life,” Michael Ball, managing director of Denver-based Weatherstone Capital Management Inc., said by phone. “When all is said and done, it’s not a significant issue,” he added. “You’ve got the demographics that supports health care virtually better than any other industries as far as the need and growth that’s going to be coming there over the next 20, 25 years.”