You seem to be missing the premise of the argument. You're right that they hedge the downside on this individual deal, but the point is that the upside for this

You seem to be missing the premise of the argument. You're right that they hedge the downside on this individual deal, but the point is that the upside for this individual deal is still small for KPCB. So why would they do it? Not because they're expecting an upside on that deal, but because inflating the valuation of a darling at a low cost will create a frothier overall valuation market for their portfolio.