If moral judgments are nothing more than expressions of personal preferences and feelings, then we have no reason to take morality seriously. Subjectivist theories such as David Hume's emotivism and A.J. Ayer's verification principle do not explain the empirical data; people do meaningfully argue about right and wrong.
Ladiesman, people argue about opinions much more often than they do facts. I'm not sure why it is you think personal preference and feelings should not be taken seriously, these things have caused wars. People are regularly murdered over these things. Morality being subjective does not make it irrelevant, it is after all a crucial part of society. If morality is objective then you need to explain why there is so much variance in what different cultures consider to be right and wrong. Not to mention the changes in the accepted sense of morals throughout time. Personal preference and feelings are debatable and change over time, facts are not and do not.