CricleCI has 100-250 Employees, which at 1000 applicants per 3 employees means over 30,000 interviewed applicant? Seems high.
And it would seem self-evident to me that not all of their 100-250 employees were hired at that 3/1000 rate, as number of applicants will grow over time due to increased brand recognition, increased spending on sourcing/outreach, etc.
Policies tend to just get stricter and stricter over time, especially with every bad experience they have (only takes one or two usually before these people go off the deep end trying to correct for it).