Is morality just a subset of reason?

[Hobbes' Choice]

Well, it may not be your position but the statement itself sounds like moral absolutism. And you have yet to explain how my post was "nothing" or was unrelated to what you were saying.

I DID NOT SAY IT.

You still haven't answered my question: What good does your definition do for society? How does defining morality as rationalizing one's pre-existing feelings help people to make better moral decisions?

I've not defined morality. But were that definition true, the effect it had on society would not make a difference to the validity of its definition. You are asking a question equivalent to the thought that god cant be true because people would not like it - so god must be real because the idea of god is important.

Morality changes, that much we do know. It changes year by year, and country by country; culture by culture. Many moral systems have similarities due to sharing common roots, or having common problems. Some systems favour the rich and powerful; others tend to assume the rightness of equality. Most are strange incompatible mixtures of both thoughts, were lip service is given to racial and social equality, but the system is used to mask the reify those same inequalities. Religion is particularly adept at this deception. And political systems designed to address those problems are soon colonised by those that are looking out for themselves.

So to answer your question: who ever this was about "better" moral decisions? Surely you could only have a "better" system if you thought morality was objective?
Most people comply to avoid social sanction; everyone challenges the boundaries, some more than others and many find themselves in the position of having to break rules to survive, whilst others break rules to invoke change; others to avoid misery of compliance. Moral rules cannot apply evenly, as we are all different and have different needs. Given these facts it is easy to see why morality is always in a state of flux, and susceptible to the machinations of power, ever changing.