In the aforementioned article, I feel something basic is overlooked. Empathy is instinctive and not something you have to work at. If you have the empathy instinct, life often requires the opposite: as there are times you have to work at not having it.
For example, when someone gets stuck by a needle, your reaction is to flinch, and you feel the unpleasantness yourself. If you have too much empathy, then it can hamper your ability to be a medical surgeon, unless you learn the ability to turn off the instinct. The same with being a mental health therapist, if your clients are in pain you will be distressed as well. Unless your empathy instinct is low or missing altogether.
Another question to ask, is, do you have empathy for all persons, or only those you admire or look up to? “You can easily judge the character of a man by how he treats those who can do nothing for him.” —Malcolm S. Forbes