I'm not sure which of us misunderstood it, but my interpretation of their findings is that overall, increased protein intake was not associated with increased athletic performance. However if you look ONLY at endurance, it was actually associated with high performance, though only when alongside carbs. Maybe counterintuitive.
Their total sample size was around 300 or 400 iirc. Pretty big, but could be better.

You can't really be "wrong" about an opinion on a video game