I think boffinism's comment below hits it, but to also add -- its important to try and find a charitable interpretation of comments when possible. Here I think empathy was meant literally as understanding other people's needs and points of view. If you don't know people with some problem directly, and also don't know how to find them -- how sure are you that the problem you are solving is real and in need of a practical solution? You have to understand user needs very well to build a novel product that people want to use. Its not about software startups solving the worlds problems -- I think its just a very general point about solving problems you understand and not ones you don't have any experience with.
To give a more concrete example, I know of a successul life insurance company. It was started because the founders had a bad experience with purchasing life insurance. They then worked with (and as) life insurance agents to better understand the customer (and insurer's) needs. THEN they built a company, one solution at a time.
Q: I am having trouble understanding why people think / do X
A: You should talk to people who think / do X and ask them why they think / do X. Until you do so, you lack sufficient empathy to address their issues / change their behavior.
Its good feedback that it is worded in a way that has ambiguous meanings, one of which (you are a sociopath) is an unwelcome character judgement. But IMHO the charitable interpretation is perfectly practical and important feedback: Don't build products for users you can't talk to and learn from.
To give a more concrete example, I know of a successul life insurance company. It was started because the founders had a bad experience with purchasing life insurance. They then worked with (and as) life insurance agents to better understand the customer (and insurer's) needs. THEN they built a company, one solution at a time.