YC states their lead ethical underpinning in the first line of their Founding Principles: "Startups are on balance a good thing." They go further in describing

YC states their lead ethical underpinning in the first line of their Founding Principles: "Startups are on balance a good thing." They go further in describing their goal to support and advise founders; and include phrasing about their philosophy of being "benevolent" to founders. Their Principles also describe prioritizing mission-driven endeavors over money. You or I may not share their ethics, but they have theirs.