I don't think that's true... YC funds plenty of inventive companies (sometimes based on idea alone). Still, the onus is on the founders to articulate why they're the ones to pull it off and how their inventions could plausibly become billion dollar companies.
Then don't say "YC will not fund the company that will invent something new."
YC openly talks about how validating your idea and growing the business are big signals to them that you are worth the investment. But while that's the most common path, there are clearly alternatives. They are just giving advice on what might maximise your chances with them.
