I think in general we take the "understanding" part in empathy too lightly. I would say we use "empathy" a lot when we are actually talking about compassion. Since the inner experience is never completely shareable, it's hard to talk about real understanding. Not trying to get philosophical here, we will probably agree that a reasonable level of understanding is both possible and sufficient. But I feel like too often there's way more "rationalization" than actual understanding, and we make the (in my opinion) mistake of calling that "empathy".

With this in mind, I would say empathy is always socially positive. If we were talking about compassion, I would share more your opinion, but I'd still say it's positive as long as we do not completely swap it for empathy.