The article seems to be misleading. Then again, I'm not a US citizen so I'm not as familiar with their parochial tax laws.
When one of my mutual funds disposes of an asset at a profit and recognizes a capital gain it simply retains the earnings and plows them back into some other capital investment, thus growing the net asset value per share (NAVPS). When I sell units of the mutual fund, I am subject to capital gains tax (or can claim a loss) as appropriate. From time to time a fund manager may choose to pay a distribution classed as a capital gains distribution, in which case it's income I treat as capital gains on my taxes. No taxes are paid by the mutual fund and I only pay capital gains tax when I redeem units of the fund.
When one of my ETFs makes a trade of underlying securities and realizes a capital gain, it's a flow-through situation. What happens is the ETF adds up all the gains and losses from transactions over the year and at the end of December I get a special kind of distribution called a "return of capital" which is like a capital gains distribution on which I need to pay taxes, but I also add it to my adjusted cost base so I don't get taxed twice and I don't actually receive any income.
As far as I understand it, that's the way mutual funds and ETFs work in the USA, too. There's no reason a mutual fund couldn't do flow-through like an ETF does, other than it would require a greater understanding of basic accounting so it wouldn't be appropriate for Mom and Pop Sixpack who would probably steer clear of having to recalculate their ACB on an annualized basis let alone understand why they need to pay tax on income they haven't received.