First of all, a system of values is not "AN ethics;" it is an ETHIC (singular). "Ethics" are the values themselves.
Now that the semantics are cleared up, I certainly can't debate what's "true" in your personal opinion. But a "rational ethic" is subject to the same flaws as any based on religion, for the simple reason that men are notoriously poor at judging their own rationality and its derivatives. Liberals are a prime example. They will defend their empty values to the death, firmly convinced in their own minds that their irrationality is fully justifiable. Never mind that their track record is deplorable. Never mind that the "logic" they use is valid under no construct known to man. In their minds, it makes sense, and all other lines of reasoning are hollow.
Besides, since logic is itself a construct, by what values do you form an ethic? Utilitarianism? Transcendentalism? Judeo-Christian cosmology? Ultimately, everything you know and believe come from the values formed over 2,000 years of Western thought. How do you propose to divorce them from Judeo-Christian influence?
Ayn Rand's Objectivism is a pipe dream, itself fatally flawed.
Yep.