In a virtual talk given last month in Los Angeles, Charlie Munger—the 97-year-old vice chairman of Berkshire Hathaway chairman and longtime business partner of Warren Buffett—issued a “dire warning on the manic momentum-driven trading activity by amateur investors and said commission-free trading apps like Robinhood were partly to blame for the bubble.” This according to a recent CNBC article.

According to Munger, the way these platforms are luring novice investors is “regrettable.”

Munger is not alone in his criticism. The article reports that Robinhood has been accused of “gamifying” investing through its app and, in lieu of charging commissions, is making money though a controversial practice called “payment for order flow”—that is, they are paid by market makers for routing trades to them.

The red-flag raising referred in part to the “jaw-dropping GameStop mania” that occurred when a “wave of at-home traders encouraged each other on a Reddit chat room to pile into shares of the brick-and-mortar video game retailer, creating a monstrous short squeeze that saw the stock soar 400% in one week.” Munger highlighted the threat that exists of clearing house failure, which he said “gets very dangerous.”

According to Munger, “The frenzy is fed by people who are getting commissions and other revenues out of this new bunch of gamblers.” He warned, “No one should believe Robinhood trades are free,”   adding, “it’s really stupid to have a culture which encourages as much gambling in stocks by people who have the mindset of racetrack bettors…It’s a dirty way of making money.”

A Robinhood spokesperson characterized Munger’s comments as “disappointing and elitist,” rebutting, “It should be celebrated that we are seeing market investors begin to diversify, and that education and awareness about the values of investing are diffusing further into previously untapped generations.”