In section B. "On the other hand, the impact of the CDC's Title 42 Orders on immigration are ameliorated by certain exceptions and "safety valves" in those orders. The CDC's Title 42 Orders grant DHS discretion to except non-citizens from the impact of the orders on a case-by-case basis.241 These exceptions can be triggered by "consideration of significant law enforcement, officer and public safety, humanitarian and public health interests."
And it says they've been employing these exceptions during the time 42 has been in force.
So not sure how much work it would be to except everyone on a case by case basis. But apparently they have only been doing it some.