I don't think that most of these are Protestants, but rather Catholics that separated from their Catholic roots. They have joined a variety of modern sects, groups and cults. The shared common component is antiCatholicism. In attacking Catholicism they can validate their choices, reassure themselves they (think) have eternal life no matter what they do. They keep trying, as it were, to scratch off that indelible mark and remove any mark of who they really are, Catholics who have separated from the church.
That sounds like the mark of the beast.