Extreme pro-Python statements about "one way to do it" are usually made by relative newcomers who are caught up in their enthusiasm for purity. (This exuberance is natural, and is a big part of the language adoption cycle.) Extreme anti-Python statements about "one way to do it" are usually made by outsiders viewing Python through accounts given by enthusiastic newcomers. This exuberant-newcomers-vs-skeptical-outsiders dichotomy isn't representative of the actual Python culture, which is much more sensible and practical than all of this implies. If you go to PyCon and attend talks by long-time Python folks, you won't find them advocating anything like blind adherence to "one way to do it".
To get specific, the wording in PEP 20 is: "there should be one, and preferably only one, obvious way to do it". Note that the dominant idea here is that there should exist some obvious way. It's merely preferable that there be only one way. Again: this is sensible, but it's not good fodder for newcomers craving purity, or for detractors craving straw men.
PEP 20 itself is often elevated to religious levels of importance, as if it were a design document that served as a blueprint for the design of Python. It's absolutely not that; it was written by Tim Peters (not Guido!) fully eight years after Python's first release. Here's the original email that Tim sent to comp.lang.python on 4 June, 1999: https://groups.google.com/d/msg/comp.lang.python/B_VxeTBClM0.... Note how he finishes: "If the answer to any Python design issue isn't obvious after reading those -- well, I just give up <wink>." Tim is very particular about his winks, and that's not even a <0.5 wink> or a <0.9 wink>, but a full, unqualified <wink>.
To put all of those pieces together: (1) we have a short, tongue-in-cheek document written after-the-fact. (2) It's misinterpreted as a design document for an entire language and ecosystem. (3) A secondary portion of one of its points is misinterpreted to be the entirety of the point. (4) This is done by exuberant newcomers and skeptical detractors who don't accurately represent the Python culture as a whole. This is why you get the impression that the community is adamant about "one way to do it". It's a reasonable extrapolation from the visible evidence, but it's not true.