The problem is that reverse discrimination does justify the discrimination they [cl]aim to fight. If HR considers the results of my technical interviews to be biased for the benefit of people who look like me and compensate accordingly, I then have to discriminate as I'm supposed to in order to achieve overall fairness of the recruitment process. How is that supposed to reduce biases ?

Reverse discrimination is the easy way, but it is actually counterproductive in term of reducing biases. As case of https://en.wikipedia.org/wiki/Campbell%27s_law imo, of optimizing the easy metric of enrollment ratio instead of the hard goal of fairness.