A very sad group indeed, but I think most people nowadays recognize that groups like this are nutty and not to be taken seriously. Honestly the real enemy isn’t the rabid anti-Catholic protestant clique, it is the growing mass of secularists rallying around their Saints Christopher Hitchens and Richard Dawkins. At the very least anti-Catholics hold a strong desire to know God and His truth…the secularists have a passive-aggressive apathy about anything other than the narrow material world that seems almost unassailable.
In both cases, however, the only solution is to educate our own children (and adults) and live as true Christians. With anti-Catholics, I think the best approach is a questioning one–ask them what the biblical proof is for Sola Scriptura, and then ask them who compiled the Scriptures. With secularists, the best way is to befriend them and behave in a true Christian manner, perhaps occasionally extending an invitation to non-religious events at your parish like potlucks or golf tournaments, until they ask the questions. Anything else would be perceived as aggressive fundamentalism and only serve to confirm the Dawkinsian notions about stupid “sky fairy worshipers.”