The title kind of makes it appear far less of a problem than it actually is, because according to the article, hCaptcha made multiple rude and evidence-free accusations of lying despite the author actually being blind.
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This isn't a defense, just an explanation... but it is also an explanation of why the entire idea of "we'll not give blind people a way past the CAPTCHA but just give a pass to 'real' blind people so we can pass ADA", which is that it should have been transparently obvious that this approach is completely infeasible and unscalable. As big as Google, Facebook, or Amazon are, they would struggle under the load of trying to create a system for determining who is "truly" blind... and that's still true if we ignore questions like exactly what "blind" is anyhow.
This shouldn't have gotten deployed and then become a problem; it should have been a 5 minute diversion in the meeting where it was proposed to analyze it's completely infeasible and never made it to so much as the design phase, let alone the deployment phase.
If you had a system for completely accurately identifying characteristics like "who is blind" in the presence of extremely hostile attacks on the system, you'd have something far more valuable than the CAPTCHA system itself! The whole idea intrinsically depends on having a stronger solution to the problems CAPTCHAs are meant to solve than the CAPTCHA system itself provides... it's fundamentally a logically unsound idea.