You are reading too much into choice of term. The author explains their rationale for using "vanity" quite clearly:
> In business, a “vanity metric” is a statistic that sounds good but is not very useful.
It's not about you being "vain" for reading the newspaper, it's just a parallel to another widely used term the author co-opted.
He literally says: "Our definition for vanity activity can be similar: something you do that seems more useful or virtuous than it really is."
And then he suggests that reading the news is a vanity activity.
My comment is perfectly on point. I think he is engaging in a vanity activity, by his own definition, when he suggests that reading the news is a vanity activity.
It's fine to have an opinion and a way of looking at the world. My objection is when a person claims that opinion is something more rational than it is-- while pissing on the choices other people make.