I assume that this is a just alarmist journalism, since water for tea/coffee is heated to boiling, and all the taps in the bathrooms say some version of 'non-potable'.
Boiling at elevation is different to boiling at sea level.
To kill Cryptosporidium (etc) you need a rolling boil for 1 minute (no one does this) ... and that's at sea level. At > 2km up you need to run that for > 3 minutes (and absolutely no one does that).
And all this is before I even get started on the woefully uncivilised idea of using 100C water for green tea.
When I mentioned the >2km 'elevation' I meant in an airplane, which typically cruises around 10km ... but are pressurised, as you note. Unfortunately they're pressured to be around 2.4km (effective). Some newer planes will pressurise to around 1.8km but these are uncommon.
In any case, water boils at '2.4km effective' at around 92C ... and therein lies the problem.