We don't really do the whole calling people stupid or flaming around here. You can make your point and leave it at that or don't comment. This sort of behavior will get you banned by the very active mod team in the future. You can refresh yourself on the guidelines of the site: https://news.ycombinator.com/newsguidelines.html
Here's a section just for you:
"When disagreeing, please reply to the argument instead of calling names."
If their premise was "lack of empathy is the defining characteristic of fascism", that makes their post a tautology. How I read it was:
> Fascism is a lack of emotional intelligence, which is basic intelligence. Empathy and compassion are a form of basic intelligence. (_AND THEREFORE, fascism lacks empathy and compassion_)
This doesn't follow. Fascism can be a lack of emotional intelligence, emotional intelligence can be a form of basic intelligence, empathy and compassion can be a form of basic intelligence, and it can still be the case that you lack emotional intelligence but have empathy and compassion (you might simply lack in other aspects of emotional intelligence).