TP’s use of the term “crowd level” (or CL) is kind of a misnomer. They aren’t measuring crowds, but wait times. As a result, it can be confusing.
Having said that, there is a strong correlation between the wait times and crowd levels, so in MOST practical situations, it comes to the same end. But, reduced staffing can actually cause inflated CLs as well, because the wait times will go up when fewer employees are operating a ride. Similarly, if there is less to do (fewer shows, or eateries open, etc), then even with lower numbers of people in the parks, the are all going to the same reduced number of rides, which drives up wait times.
When park capacity is limited, it MIGHT reduce CLs…but during COVID, not only has park capacity been limited, but there has been a lot less open for folks to do, so the impact on CLs is a bit wonky.