> On the same page: "All nouns that end in –ei, –heit, –ie, –in, –keit, –schaft, –tät, –ung are feminine."

I would hazard the guess that, in this explanation, the author refers to syllables and not just a combination of letters.

The counter-examples you gave all end in syllables different from those mentioned by the author:

der Brei - one syllable / das Aller-lei / das Ben-zin