It is possible to feel sadness and to transcend it at the same time. I have been fortunate enough to meet a few truly wise people. None of them were indifferent. I have also met people who wished they were wise but have mistaken indifference for equanimity. If equanimity is the ability to surf big emotional waves without wiping out, indifference is the refusal to get into the water.
Many years ago I was introduced to the idea of spiritual bypass - this is when we try to use spirituality to avoid our messy human experience. It's is like going to Knott's Scary Farm and rigidly insisting that everyone is an actor. Yeah. But. You're not fooling anyone. If you really had the balls, you'd let yourself scream.
That said, the wiser I get, the less I use empathy when I meet those who are suffering. I can be fully present with someone who is broken-hearted without focusing on my own broken heart. I can feel the sun's warmth without thinking about the heat radiating off of me. Likewise, if I am in the presence of someone who is sad, I may notice physical feelings of sadness in my body - a clench in my chest, a vibration in my throat. To resist this would be like resisting the sun's warmth. I notice and if I need to, I move. At same moment I'm probably watching other things as well.
For example, say I am sitting with a client who is sobbing because her abusive boyfriend has left her for another woman. I can resonate with her grief, I can witness how it has roots back to her childhood, and how, for her, it relates to hunger and comfort and desire. At the same time, I can feel proud of her courage to express her feelings authentically, and hopeful about how she may use this experience to become wiser herself.