Just got bashed several times, while presenting the fragility of values idea in Oxford, for using the term "descriptive morality".

So it's even worse than I thought? When ethicists do any "descriptive" research, they are studying morality, whether they care to admit it or not. The problem with calling such things "ethics" is not so much that it implies a pluralist/relativist view - if anything, it makes the very opposite mistake: it does not take moralities seriously enough, as they exist in the real world. In common usage, the term "ethics" is only appropriate for very broadly-shared values (of course, whether such values exist after all is an empirical question), or else for the kind of consensus-based interplay of values or dispute resolution that we all do when we engage in ethical (or even moral!) reasoning in the real world.