My view is that it's both, since it takes small steps to achieve the greater goal (a ban on all fur products), but I don't see how it's any worse buying dog fur than mink fur. Personally I don't purchase leather or meat either, but realistically a ban on all fur products is more likely in the foreseeable future.
http://www.timesonline.co.uk/article/0,,3-2462423,00.html
http://www.timesonline.co.uk/article/0,,3-2462423,00.html