Yes, it is a "classic", and actually the linked to online version (with the illustrations) is (besides being not complete) somehow much worse (IMHO) than the original, which is a very plain booklet where the cartesian diagrams are less distracting, here it is (from archive.org), the PDF is an actual scan of the booklet:
https://archive.org/details/The_Basic_Laws_of_Human_Stupidit...
More history about the Author and the book is here:
http://gandalf.it/stupid/cipoleng.htm