Even smaller drop: it's 148,000 members. Statistically, yes, it's only a miniscule percent who have resigned or are protesting by withholding dues, but that does not include the many others who have signed petitions, written letters of protest, etc.  I don't have the numbers on those.

This issue is really  hurting the APA on many, many levels.

And sometimes it doesn't take huge numbers to make a difference.  When well-known psychologists start resigning in protest and publishing their reasons and objections, it makes a difference.  Already there is talk among other psychologists who have seen Ken's later that they, too, may resign. Certainly, it will keep the issue alive and discussed.  And it is an issue that needs to be kept on the forefront of discussion, particularly in light of this administration's use of torture techniques.