Why Does Adobe Acrobat Dc's "crop Pages" Fail To Crop My Pdf?

Please see the GIF below. You can download the PDF here.
https://s6.gifyu.com/images/Acrobat-not-cropping-Roger-Smiths-Property-Law.gif
Here's my goal. In the PDF, all pages are bordered by white blank space, but the white blank space start at different lengths from the border. Scilicet, the cutoff and dimensions of the text and images differ for each page.

Unquestionably it's too inefficient to measure the cutoff of white blank space on each page. So I'm cropping to eliminate the maximum white space, without cropping any of the substantive content.

 

If you can't see the GIF, please see it on [URL]https://powerusers.codidact.com/posts/282135[/url].