Co-incidentally, I just watched a movie on DD yesterday and have been reading her book "On Pilgrimage". I think we have to establish why many people see her as a good role model before criticising her. If you start with the principles of the corporal and spiritual works of mercy, and the story of the Good Samaritan etc, and take from them the lesson that we ought to help those less fortunate whenever we can and see Christ in them, then DD gives us a marvellous example of love of neighbour in action, primarily with her soup kitchens and hostels for the homeless. But, do not read DD to find guidelines for political action, or for liturgy. She is misguided and confused on both, as any modern (relatively modern) Catholic in the NO may be. When many clergy are teaching the wrong stuff, is it any surprise to find the faithful are absorbing it? But her love for Christ's poor, her desire to dedicate her life to Christ through helping His suffering creatures is spot-on, and her charity is examplary.
Bottom line: don't read DD in order to learn about the correct political attitude to take or to be edified by her "trad" credentials. Read her in order to understand the great need to help the wretched and the suffering, and how one may do that in practical, immediate circuмstances (such as helping beggars and the homeless).