Naming empathy as the most important thing for a project is not even correct if you are doing homeless shelter charity work.
The biggest problems I've had in projects has always been of techical nature, or people failing to understand problems of techical nature, not people failing to feel with other people.
In my 15 years in web software development, my experience has been exactly the opposite. In fact, all the technical problems came from people problems.
"Empathy" may be too narrow or too loaded a word, but I agree with the idea here.
> people failing to understand problems of techical nature
You may be illustrating the problem yourself here, if you'll allow me to be a bit presumptuous.
It is the technologist's job to prevent failures of understanding. Believing that everyone else thinks/feels exactly the way you do is often how misunderstandings happen.
It can only make competent technologists and receptive junior technologists who wish to learn better. Caring what the dead wood thinks is a recipe for an inferior product.
Empathy is not a solution for turning dead wood into live wood. There's negative value in making incompetents feel like equal members of a team.
Empathy can even be utilized used to fuel drama. It doesn't have to be used for good. If you are surrounded by asses no amount of empathy will help.
The advice can just as well be "work with nice and kind people - they make great teams together". Empathy in this case is just a buzzword for something obvious.
Empathy is maybe one of the most important skill for therapist.
Maybe some developers believe that this Empathy guy is another one of these HR/Agil/Scrum Consultant making big money telling others how they should feel better and be happier in an one hour session in a big hall to tick of a check box in the employee education program when their main concern might be parking space in the morning, some hard task at work or forced attrition etc.
Especially with the implicit insult if you don't agree social trick. That really raises the "sociopath" flags and thus they get resoundingly told to get lost.