How can there be an "index" bubble like at the bottom of the infographic. Who cares how the funds are invested? It's this exactly equivalent to saying there's a

How can there be an "index" bubble like at the bottom of the infographic. Who cares how the funds are invested? It's this exactly equivalent to saying there's a general stock market bubble, which he says earlier? Why does it matter if a large part of that money is being invested by index funds?