Not everyone on Earth is an American :)

As wpietri correctly assumed, I thought that a 401k was by definition a managed fund and my comment was directed at managed funds in general.

Also, after switching employers, you can roll your 401k over to an IRA and invest in whatever you want.

It wasn't my comment, but I suspect his focus was more on the managed funds that most people use in 401ks rather than the 401k account type itself.

That's a reasonable suspicion. Warren Buffett's involved in a million-dollar bet on the same topic: http://longbets.org/362/