Hi Amira-
Some notes:
-On this particular matter, you are correct (not the writer), the second witness is only required as 'backup'. This is because when the Quran was revealed, women had little education, and therefore were liable to error in the matter of financial testimony. In the eyes of God, the testimony of a man and a woman are equal, this can be identified in Surah al-Nur and the case of zina.
- I would like to caution you against using any writing sourced from self proclaimed "Muslim feminists". These deviants only seek to overhaul and replace the Quran with their own Westernized, liberal mindsets, to correct "patriarchal influences" or some similar nonsense. They claim that the Quran is "sexist" and that it's clear directives on things like inheritance must be "reformed" to make it approvable to them
-I firmly believe that the Quran views men and women as complete equals in the eyes of God, and bestows upon women numerous rights and privileges that would have been alien to them at the time. However, that does NOT mean that Islam is 'feminist'. Feminism is an ideology that is in direct opposition to the Quran, and any attempts to try to interpret Islam according to its whims should be opposed.
-As Quran centric Muslims, we should remain wary of any biases that come into play when individuals interpret the Quran, whether they be from the "traditionalist, orthodox" camp, or the "modern, liberal" camp.
Regards
wanderer