> As such I believe quotas are a good thing
You don't address the article's claim that quotas make stereotype threat worse.
This is a real, lived experience. In high school, I (an overrepresented minority) failed to get in to MIT, and my best friend (an underrepresented minority) got in, despite me looking better 'on paper'[0]. He chose not to go even though I pled with him that it would be a better life choice. Not going to MIT was disastrous because his college experience was bad, including an unjustified arrest, and dropping out. Don't worry, it all worked out - he's the CEO of a startup that's doing well now. I can't claim to know what was in his mind in high school but a part of me thinks there was real stereotype threat in play.
Second issue with quotas: In the case of Harvard with their overrepresented minority, they usually reject based on soft qualities like "no leadership potential". This really irks me, as my father in his government job was denied promotion several times because of that exact phrase, "no leadership potential". This is considerably ironic since for a brief stint he took a sabbatical and went full-time with his job in the navy, as an O-6 (captain, as in Picard, not America). During this year, the team he commanded completed the US Navy's first ever fully databased inventory system, on time and under budget, saving the navy billions of dollars. "no leadership potential" and phrases of its ilk are basically cover for discrimination, as they can be so easily issued even in the face of blatant evidence to the contrary.
[0] for example I had great scores in the AP sciences and a high-performing science fair project that placed at the international level - which are relevant skills for MIT.