PDF Printing Quality Issues
I have observed this problem before: seemingly solid-tone 100%K text or other vector image in a PDF gets printed out with a 'dotted' pattern.

The problem is caused by color definitions in the PDF file, which get rasterised into 'half-tone'. So you end up with an object that is 100% Black, but comprised of dots, rather than solid tone.

The solution is to make sure that Color Matching is switch to "In Printer" and NOT to "ColorSync". This for Preview and other Apple apps. In Acrobat, use "No Color Management".

I printed sample pages from your exemplar PDF, and they were fine. The PDF is non-optimal, admittedly, as there is Transparency and mixed CMYK and RGB objects.