One of my favorite readings from undergrad and grad school was "The Problem of Social Costs" by R. Coase. I'm sorry you think externalities are glossed over by economics, but Im excited to tell you that this is certainly not the case. Coase won the Nobel Prize in economics in large part for his work on externalities. They don't hand out Nobel prizes for glossed over topics. It's definitely worth a read of you wish economics paid more attention to externalities:

https://www.law.uchicago.edu/sites/default/files/file/coase-...

I suspect the person you are replying to was not referring so much to academic economists as a whole (which would include Coase and Piketty and even probably Marx) but rather the mercenary subset of economists who get signal-boosted by powerful interests in order to promote the self-serving narrative of the day, and yeah, that subset of economists dodges subjects like inequality and externalities with more finesse and agility than Neo dodging bullets in the matrix.

The gutter mud soaked knife-fight practice of economics and the erudite study of economics is one of the more jarring discontinuities between how we talk about how something works and how it actually does.

The consideration of externalities that don't impact the bottom line is so alien to the real observation of the rites of capital that it might as well be written on the inside of a particularly boring rock in the oort cloud.

They don't hand out Nobel prizes for glossed over topics.

Leaving aside the fact that the Economics prize isn't actually a Nobel Prize, topics which historically haven't been given enough attention are exactly where the highest impact research takes place.

If externalities had always received the attention they deserved, Coase would have never received his prize, because his work would not have been so important.