So as an update. I did the WBR 4 lap flat race this morning and you could only see racers. This is the same group but different race than the one where I saw all Zwifters (the WBR 3 lap hilly). So either the race creators are updating their race settings, or zwift is doing it for them. Either way, it is much better when all you can see are racers. All races should do this.