For my two cents, I think this is a rather narrow point of view, even though it has some merit. Giving your money to an asset manager, as part of a sensible investment strategy, is not dumb providing you are making an informed decision. It's not to say Buffet was wrong, far from it. But it's not the whole story. Investing in active strategies involves taking on all the risks that come with pursuing active mandates. But this does not mean that all active managers have no value.
It needs to be remembered that not all active managers are simply trying to beat the market. Some are trying to provide downside protection in the knowledge that they will give away upside in momentum driven markets. Others, like many hedge funds, are trying to deliver an alternative or low correlated source of equity market beta.
Yes, the majority of active managers do not beat a broad market index (let alone index funds). Yes, performance persistence is a real obstacle. Personally I believe that a great many investors in managed investments, in the absence of the ability or resources to make informed decisions, are probably better off using low cost market cap weight index strategies rather than active managers. But the whole active vs passive debate is more nuanced than just saying "Giving your money to an asset manager is dumb".
