See #596.
If I were this ignorant about a topic I would be embarassed to try to debate it.
From your link: "If all data points lie on a straight line, this line is called an isochron. The better the fit of the data points to a line, the more reliable the resulting age estimate."
So, where the data does not meet the 'a priori' assumptions, it is *assumed* to be in error and thrown out as 'unreliable'. Truth by definition.
Take your own advice.