Arguments that exchange-traded funds increase market volatility or can even cause a market crash are popular these days, and the Facebook stock tanking provided one more chance for the ETF naysayers to make their case.
It also provided one more opportunity for Vanguard Group founder and index fund pioneer Jack Bogle to say it's most likely a bogus argument.
There are more than 100 ETFs with Facebook among their top holdings. There are more than 230 ETFs with exposure to Facebook.
What does Bogle think of the latest ETF market crash Exhibit A?
"I'm gonna guess we don't know, but I will guess the answer is 'no,'" Bogle told CNBC in an interview Thursday.
The reason is simple, and it's one Bogle has made before: active managers more or less replicate the indexes just like passive funds.
"If you look at the hot stocks, U.S. active managers own almost exactly the same as passive index managers, there's not much difference."
The ETF industry did experience net outflows in February and March, the first time since 2008 there were negative flows in two consecutive months. And Bogle did tell CNBC that in 66 years he has never seen volatility like this.
However, "most ETF investors are buy and hold investors (both advisory and retail accounts)," noted Neena Mishra, head of ETF research at Zacks Investment Research.
Indeed, Bogle told CNBC on Thursday that what we've seen in the market is lots of selling of Facebook shares, not lots of selling by ETFs.
At last year's annual Morningstar investment conference, Bogle answered a question about passive management's rise being a major risk to the market this way:
"If indexing even got up to 50 percent to 60 percent of the market ... still the markets would be efficient and work just fine." He went on: "It's a reasonable question but there's no evidence it happens. All speculative managers hold Apple and Amazon and Alphabet. Active managers own roughly the same percentage of those stocks as the index weight ones. One doesn't want to be too dogmatic, but I don't believe there will be a significant impact."