John “Jack” Bogle is an icon in the investing industry. The founder of Vanguard and the “father” of index mutual fund investing has had a lot of good ideas over the years. Unfortunately, the ideas in his recent editorial in the Financial Times are not among those good ideas. According to Mr. Bogle, exchange-traded funds (ETFs) are something that investors should “beware” of. As Bogle writes, “Mark me as a member of a small group of cohorts who are dubious about the utility of ETFs for long-term investors.” Bogle goes on to express some rather bad views about ETFs as...