I don't think the thread is turning ugly -- it is an important topic, and the fact that a tiny minority seek to derail it should not be reasons for deleting or locking it. If that were established as a precedent, then it would be only too easy for someone in the future to deliberately derail a thread just in order to get it removed or locked. Those of us interested in civilised debate are quite capable of ignoring those who are not.
** Phil.