It is a sensible position. YC and VCs are backing businesses, not charitable causes or research initiatives. It is the founders' responsibility to liaise the two sides in order to signal that the pursuit of their particular purpose is an undeniably attractive and fast-growing investment. Which obviously entails more work and has fewer market opportunities compared to the case "money is the purpose".

After getting backed and receiving adequate funding, all that matters is maintaining a good growth rate to remain a purpose-driven business.