That's true, but it only solves one side of the problem, where unqualified people won't get hired by pure networking. If people only get hired by networking plus performance, it still means that capable people who are pushed out of effective networking (for any of a host of reasons) will lose opportunities. They might not get bad recommendations, they simply won't be on anyone's list to call.

Even worse, it's quite possible for discrimination to become a disincentive to recommending someone, just like incompetence would be. Someone who won't be well-received for personal reasons is effectively a "bad candidate" with the potential to damage the recommender's reputation. The result is that even a person who overcomes barriers to find network connections won't necessarily be able to draw on them effectively.

(A past-tense example to cut down on politics: a Liar's Poker trader wouldn't recommend a friend who couldn't sell, but they also wouldn't recommend a skilled trader who wasn't a friend. And if they had recommended a skilled friend who wasn't a white guy, they could have expected at least as negative a reaction as if they'd recommended a bad trader.)