Let me explain it with a theoretical example: you are a company and the field you’re hiring in consists of 90 women and 10 men. You need 10 people for the job and want the most capable. Statistically that would mean hiring 9 women and 1 man on average, giving you the 10% most capable employees. But since you want equality you want it 50/50, so you hire 5 women and 5 men. That means that for the women you hired the 5,6% most capable employees, but for the men you hire the 50% most capable employees. So you get less capable employees this way, assuming both groups are equally likely to be capable.
Qwant and Ecosia are also developing a fully European search index together. The first versions are expected to be available this summer.