But saying "index funds free-ride on the work done by active investors" and then following with "no one thinks that active managers should be able to charge for their services, is a world that will spend too little time and effort on allocating capital to the right businesses" is FUD.
The value of the market represents the sum total opinion of everyone in it (plus noise), not just the managers of mutual funds losing business to index funds. Frankly, it sounds like the griping of someone telling fund managers that they deserve their fees, but the supposed loss from using index funds described in the original article (~.2%) is still dwarfed by the increased fees of actively managed funds.
Most index fund expenses are around .1-.2%, while most active funds come in at a whole 1-2%. To justify the cost of an actively managed fund, a manager has to not just beat the market, but trounce it. Very, very few can do so for any length of time, and they know it, which is why articles trying to convince people of the virtue of active fund management are constantly written. Unless your manager is as good as Buffett, buy an index fund.
The math is simple, but there's many fund managers out there trying to convince you otherwise.