That's because the Zen is a collection of fuzzy aphorisms about taste. Python has in fact never had a set of hard principles that constrain the design of the language.

In other traditions, type systems or the borrow checker or even vaguer things like a commitment to a "tiny core" of just a few primitives constrain language designers in a way that (sometimes inflexibly) commits them to the consequences of earlier design decisions. Python has mostly been designed one step at a time, by fiat. It's not a surprise that the result is an inconsistent language, especially after the resignation of the BDFL, and especially after so many years of widespread popularity.