Long story short, this is only in some cases. In other cases, which the enemies of Islam don’t like to bring up, a woman’s witness is sufficient, while the man’s witness is not accepted at all. In many other cases, a woman’s testimony is exactly the same as a man’s. In fact, in the most important cases, where the actual transmission of narrations of Hadiths is either being classified as authentic or not, a woman’s testimony is exactly the same as a man’s. Therefore, in cases where one male’s testimony is equal to two women’s testimony, it doesn’t have to do with the women, rather, it has to do with the situation itself. Numerous scientific studies have even shown and made it very clear that when it comes to abilities such as spatial awareness and spatial abilities in general, men are significantly better at its performance than women. And this is perfectly fine! Men are better than women in somethings and women are better than men in other things, and this is not a form of injustice at all.
And Allah knows best.