Recent news that e-cigarettes may be linked to hundreds of cases of severe lung disease across dozens of states has refocused public attention on the potentially harmful effects of vaping. As many as six people have already died of severe respiratory illness brought on by use of e-cigarettes. On Wednesday President Trump announced a Food and Drug Administration ban on many flavored vaping products citing safety concerns, calling it “a new problem.”

But while critics of e-cigarettes have seized upon recent tragedies to demand...