Note that individual value differences (like personal differences in preferences/desires) do not imply a difference in moral priority. This is because moral priority, at least judging from a broadly utilitarian analysis of the term, derives from some kind of aggregate of preferences, not from an individual preference. Questions about moral priority can be reduced to the empirical question of what the individual preferences are, and/or to the conceptual question of what this ethical aggregation method is. People can come (or fail to come) to an agreement on both irrespective of what their preferences are.
Note that individual value differences (like personal differences in preferences/desires) do not imply a difference in moral priority. This is because moral priority, at least judging from a broadly utilitarian analysis of the term, derives from some kind of aggregate of preferences, not from an individual preference. Questions about moral priority can be reduced to the empirical question of what the individual preferences are, and/or to the conceptual question of what this ethical aggregation method is. People can come (or fail to come) to an agreement on both irrespective of what their preferences are.